Nucleobase Transport Proteins
Purine-Pyrimidine Metabolism, Inborn Errors
Nucleoside Transport Proteins
Chromatography, High Pressure Liquid
Utilization of exogenous purine compounds in Bacillus cereus. Translocation of the ribose moiety of inosine. (1/498)Intact cells of Bacillus cereus catalyze the breakdown of exogenous AMP to hypoxanthine and ribose 1-phosphate through the successive action of 5'-nucleotidase, adenosine deaminase, and inosine phosphorylase. Inosine hydrolase was not detectable, even in crude extracts. Inosine phosphorylase causes a "translocation" of the ribose moiety (as ribose 1-phosphate) inside the cell, while hypoxanthine remains external. Even though the equilibrium of the phosphorolytic reaction favors nucleoside synthesis, exogenous inosine (as well as adenosine and AMP) is almost quantitatively transformed into external hypoxanthine, since ribose 1-phosphate is readily metabolized inside the cell. Most likely, the translocated ribose 1-phosphate enters the sugar phosphate shunt, via its prior conversion into ribose 5-phosphate, thus supplying the energy required for the subsequent uptake of hypoxanthine in B. cereus. (+info)
Tissue distribution and characteristics of xanthine oxidase and allopurinol oxidizing enzyme. (2/498)Tissue distribution and levels of allopurinol oxidizing enzyme and xanthine oxidase with hypoxanthine as a substrate were compared with supernatant fractions from various tissues of mice and from liver of mice, rats, guinea pigs and rabbits. The allopurinol oxidizing enzyme activities in liver were quite different among the species and the sex difference of the enzyme activity only in mouse liver. In mice, the highest activity of allopurinol oxidizing enzyme was found in the liver with a trace value in lung, but the enzyme activity was not detected in brain, small intestine and kidney, while the highest activity of xanthine oxidase was detected in small intestine, lung, liver and kidney in that sequence. The allopurinol oxidizing enzyme activity in mouse liver supernatant fraction did not change after storage at -20 degrees C or dialysis against 0.1 M Tris-HCl containing 1.15% KCl, but the activity markedly decreased after dialysis against 0.1 M Tris-HCl. On the contrary, the xanthine oxidase was activated 2 to 3 times the usual activity after storage at -20 degrees C or dialysis of the enzyme preparation. These results indicated that allopurinol was hydroxylated to oxipurinol mainly by the enzyme which is not identical to xanthine oxidase in vivo. A possible role of aldehyde oxidase involved in the allopurinol oxidation in liver supernatant fraction was dicussed. (+info)
Oxypurinol administration fails to prevent free radical-mediated lipid peroxidation during loaded breathing. (3/498)The purpose of the present study was to determine whether it is possible to alter the development of fatigue and ablate free radical-mediated lipid peroxidation of the diaphragm during loaded breathing by administering oxypurinol, a xanthine oxidase inhibitor. We studied 1) room-air-breathing decerebrate, unanesthetized rats given either saline or oxypurinol (50 mg/kg) and loaded with a large inspiratory resistance until airway pressure had fallen by 50% and 2) unloaded saline- and oxypurinol-treated room-air-breathing control animals. Additional sets of studies were performed with animals breathing 100% oxygen. Animals were killed at the conclusion of loading, and diaphragmatic samples were obtained for determination of thiobarbituric acid-reactive substances and assessment of in vitro force generation. We found that loading of saline-treated animals resulted in significant diaphragmatic fatigue and thiobarbituric acid-reactive substances formation (P < 0.01). Oxypurinol administration, however, failed to increase load trial time, reduce fatigue development, or prevent lipid peroxidation in either room-air-breathing or oxygen-breathing animals. These data suggest that xanthine oxidase-dependent pathways do not generate physiologically significant levels of free radicals during the type of inspiratory resistive loading examined in this study. (+info)
The mechanism of action of methotrexate in cultured L5178Y leukemia cells. (4/498)This study investigates the relationships between the methotrexate (MTX)-induced purineless state and thymineless state and between the thymineless state and the kill of L5178Y cells. As an index of the thymineless state, we measured the effect of MTX on conversion of deoxyuridylate to thymidylate. This was measured as the rate of incorporation of tritiated deoxyuridine into DNA, but it was corrected for changes in incorporation of tritiated thymidine. Thus we derived the "calculated tritiated deoxyuridine rate." During the MTX treatment, the calculated tritiated deoxyuridine rate decreased rapidly at first and then more slowly. The slow 2nd-phase block was not reversed by hypoxanthine. As the 2nd-phase block deepened, the lymphoblasts continued to die (loss of cloning ability) but recovered the ability to incorporate tritiated thymidine into DNA. After 7 hr of MTX treatment, the kinetics of the 2nd-phase block in calculated tritiated deoxyuridine rate correlated closely with the kinetics of cell kill. Thus, MTX may inhibit dihydrofolate reductase enzyme, rapidly deplete S-phase L5178Y of reduced folates, and thus produce a purineless and thymineless state. As treatment continues, MTX intensifies the thymineless state, possibly by direct inhibition of thymidylate synthetase enzyme, and the cells die predominantly a thymineless death. The purineless state initially contributes to cell kill but later does not, possibly because it partially reverses spontaneously. (+info)
Isolation of mammalian cell mutants deficient in glucose-6-phosphate dehydrogenase activity: linkage to hypoxanthine phosphoribosyl transferase. (5/498)Mutants of Chinese hamster ovary cells deficient in glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate: NADP 1-oxidoreducatse, EC 220.127.116.11) activity were isolated after mutagenesis with ethyl methane sulfonate. The mutants were induced at frequencies of about 10-4 and do not differ in growth properties from wild-type cells. They were isolated by means of a sib selection technique coupled with a histochemical stain of colonies for enzyme activity. The lack of enzyme activity is not due to a dissociable inhibitor, and is recessive in hybrid cells. Multiple mutants that lack hypoxanthine phosphoribosyltransferase activity (IMP:pyrophosphate phosphoribosyltransferase, EC 18.104.22.168) and adenine phosphoribosyltransferase activity (AMP:pyrophosphate phosphoribosyltransferase, EC 22.214.171.124) were isolated by further mutagenesis. By following segregation of wild-type phenotypes from heterozygous multiply marked hybrid cells, it was shown that the genes responsible for glucose-6-phosphate dehydrogenase activity and hypoxanthine phosphoribosyltransferase activity are linked in Chinese hamster cells, in agreement with the location of both on the X chromosome in humans. No linkage to adenosine phosphoribosyltransferase was found. The isolation of mutant cells carrying linked markers should prove useful for studying chromosomal events such as segregation, breakage, recombination, and X-chromosome reactivation. (+info)
Purine metabolism in murine virus-induced erythroleukemic cells during differentiation in vitro. (6/498)Purine metabolism was studied in murine virus-induced erythroleukemia cells stimulated to differentiate in vitro in the presence of dimethylsulfoxide. The activities of the enzymes that catalyze the synthesis of the first intermediate of the de novo purine pathway, phosphoribosyl-1-amine, were decreased while the enzymes that catalyze the conversion of purine bases to purine ribonucleotides remained unchanged at the time the cells acquired the specialized function of hemoglobin synthesis. In addition, cytidine deaminase (cytidine aminohydrolase, EC 126.96.36.199) activity increased with erythropoietic maturation, as it does during murine erythropoiesis in vivo. Stimulation of cellular proliferation of stationary erythroleukemic cells resulted in a marked increase in the activities of purine biosynthetic enzymes. These data provide a convincing example of repression and derepression of the PRA synthesizing enzymes in mammalian cells in vitro, and further evidence that the regulatory mechanisms operative in the normal development of erythrocytes can be activated by exposure of erythroleukemic cells to dimethylsulfoxide. (+info)
Consequences of methotrexate inhibition of purine biosynthesis in L5178Y cells. (7/498)Addition of 1 muM methotrexate to cultures of L5178Y cells results in an initial inhibition of thymidine, uridine, and leucine incorporation into acid-insoluble material followed, after about 10 hr, by a partial recovery in the extent of incorporation of these precursors. Acid-soluble adenosine triphosphate and guanosine triphosphate concentrations are greatly reduced initially, but guanosine triphosphate concentrations appear to recover partially by 10 hr. Acid-soluble uridine triphosphate and cytidine triphosphate concentrations initially increase after methotrexate treatment but then, with time, they too decline. Hypoxanthine and guanine are more effective than is adenine in overcoming the methotrexate-induced inhibition of thymidine incorporation. These results suggest that, in the presence of methotrexate, guanine nucleotides become limiting for nucleic acid synthesis before adenine nucleotides do. The block of purine de novo synthesis in L5178Y cells by methotrexate is almost complete and is not reversed with time. This suggests that the additional purine nucleotides that are available for nucleic acid synthesis 8 to 10 hr after addition of methotrexate are being derived from nucleic acid breakdown. Consistent with this is the observed reduction in the number of polyribosomes and hence, presumably in messenger RNA levels. (+info)
Growth of human diploid fibroblasts in the absence of glucose utilization. (8/498)Normal human diploid fibroblasts were able to undergo one to two cell divisions without glucose utilization in Eagle's minimum essential medium plus 10% dialyzed fetal calf serum if the medium was supplemented with hypoxanthine, thymidine, and uridine (supplemented medium termed HTU-MEM). Under these conditions, the added purine and pyrimidines were required for nucleic acid synthesis, as shown by the inability of Lesch-Nyhan fibroblasts to grow in HTU-MEM. Normal human diploid fibroblasts continued to produce lactate in HTU-MEM, but at a greatly reduced rate. Since cells grew in HTU-MEM without glucose utilization, the probable energy and carbon source was glutamine, which is present in relatively high concentration. Furthermore, the rate of glutamine utilization per cell division was 2-fold greater in HTU-MEM than in medium with 5.5 mM glucose. These results suggest that glutamine can be a major energy source for cells grown in vitro. (+info)
Hypoxanthine is a purine nucleoside that is naturally present in the body and is a precursor to the synthesis of the nucleotides adenine and guanine. It is also a component of the nucleic acids DNA and RNA. In the medical field, hypoxanthine is used as a diagnostic tool to measure the activity of the enzyme xanthine oxidase, which is involved in the metabolism of purines. It is also used as a treatment for certain genetic disorders, such as Lesch-Nyhan syndrome, which is characterized by high levels of uric acid in the blood and urine due to a deficiency in the enzyme hypoxanthine-guanine phosphoribosyltransferase.
Hypoxanthines are a group of purine derivatives that are important intermediates in the metabolism of purines. They are formed from the breakdown of nucleic acids, such as DNA and RNA, and are further metabolized to uric acid. In the medical field, hypoxanthines are often used as markers of purine metabolism and can be measured in blood or urine samples. Abnormal levels of hypoxanthines can be associated with a variety of medical conditions, including gout, kidney disease, and certain genetic disorders.
Hypoxanthine phosphoribosyltransferase (HPRT) is an enzyme that plays a crucial role in the metabolism of purines, which are important components of DNA and RNA. Specifically, HPRT catalyzes the conversion of hypoxanthine to inosine monophosphate (IMP) and xanthine to xanthosine monophosphate (XMP). These reactions are the first steps in the salvage pathway for purine biosynthesis, which allows cells to recycle and reuse purine bases that are present in the environment. In the medical field, HPRT deficiency is a rare genetic disorder that results from a deficiency in the HPRT enzyme. This deficiency can lead to the accumulation of toxic levels of hypoxanthine and xanthine in the body, which can cause a range of symptoms including liver damage, kidney damage, and neurological problems. HPRT deficiency is typically diagnosed through genetic testing and can be treated with a combination of dietary restrictions and medications that help to lower the levels of toxic purines in the body.
Inosine is a purine nucleoside that is naturally present in the body and is involved in various biological processes. In the medical field, inosine is used as a medication to treat certain types of heart failure. It works by increasing the production of adenosine triphosphate (ATP), which is the primary source of energy for cells in the body. Inosine is also being studied for its potential use in treating other conditions, such as chronic obstructive pulmonary disease (COPD) and certain types of cancer.
Xanthine is a purine derivative that is naturally occurring in the body and is a precursor to uric acid. It is also found in some foods, such as coffee, tea, and chocolate. In the medical field, xanthine is used as a medication to treat gout, a type of arthritis caused by the buildup of uric acid crystals in the joints. It works by blocking the production of uric acid in the body, which helps to reduce the amount of uric acid in the blood and prevent the formation of uric acid crystals. Xanthine is also used to treat certain types of heart rhythm disorders, such as atrial fibrillation, and to prevent the formation of blood clots.
In the medical field, purines are a type of organic compound that are found in many foods and are also produced by the body as a natural byproduct of metabolism. Purines are the building blocks of nucleic acids, which are the genetic material in all living cells. They are also important for the production of energy in the body. Purines are classified into two main types: endogenous purines, which are produced by the body, and exogenous purines, which are obtained from the diet. Foods that are high in purines include red meat, organ meats, seafood, and some types of beans and legumes. In some people, the body may not be able to properly break down and eliminate purines, leading to a buildup of uric acid in the blood. This condition, known as gout, can cause pain and inflammation in the joints. High levels of uric acid in the blood can also lead to the formation of kidney stones and other health problems.
Inosine monophosphate (IMP) is a nucleotide that plays a role in various biological processes, including energy metabolism, nucleic acid synthesis, and regulation of gene expression. In the medical field, IMP is often studied in relation to diseases such as cancer, where it has been shown to be involved in the regulation of cell growth and proliferation. Additionally, IMP is used as a diagnostic tool in the detection of certain genetic disorders, such as Lesch-Nyhan syndrome, which is caused by a deficiency in the enzyme that converts IMP to adenosine monophosphate (AMP).
Xanthine oxidase (XO) is an enzyme that plays a crucial role in the metabolism of purines, which are nitrogen-containing compounds found in all living cells. XO is primarily located in the liver, kidneys, and white blood cells, and it catalyzes the conversion of hypoxanthine and xanthine to uric acid. In the medical field, XO is of particular interest because it is involved in the production of uric acid, which can accumulate in the blood and form crystals that can cause gout, a painful joint condition. High levels of uric acid in the blood are also associated with an increased risk of kidney stones, cardiovascular disease, and other health problems. XO inhibitors are drugs that are used to lower uric acid levels in the blood and reduce the risk of gout and other complications associated with high uric acid levels. These drugs work by inhibiting the activity of XO, which reduces the production of uric acid. Examples of XO inhibitors include allopurinol and febuxostat.
Phosphoribosyl pyrophosphate (PRPP) is a high-energy molecule that plays a central role in the biosynthesis of purines and pyrimidines, which are essential components of DNA and RNA. PRPP is synthesized from ribose-5-phosphate and ATP in a reaction catalyzed by the enzyme phosphoribosyl pyrophosphate synthetase (PRS). In the medical field, PRPP is often studied in the context of diseases related to purine metabolism, such as gout and Lesch-Nyhan syndrome. PRPP is also a key intermediate in the synthesis of the anti-cancer drug 6-mercaptopurine, which is used to treat certain types of leukemia and lymphoma. Additionally, PRPP is involved in the regulation of cell growth and proliferation, making it a potential target for the development of new cancer therapies.
Inosine nucleotides are a type of nucleotide that contains the nitrogenous base inosine. Inosine is a modified form of adenine, and it is found in RNA molecules. Inosine nucleotides are important for various cellular processes, including energy metabolism, gene expression, and DNA repair. They are also used as a dietary supplement in some medical conditions, such as chronic fatigue syndrome and fibromyalgia, to help improve energy levels and reduce fatigue.
Azaguanine is a purine analog that is used in the treatment of certain types of cancer, particularly leukemia and lymphoma. It works by inhibiting the growth and division of cancer cells. Azaguanine is typically administered as a chemotherapy drug, either alone or in combination with other medications. It is usually given by mouth or intravenously. Side effects of azaguanine may include nausea, vomiting, diarrhea, loss of appetite, fatigue, and anemia. It can also cause bone marrow suppression, which can lead to a decrease in the number of red blood cells, white blood cells, and platelets in the blood.
Lesch-Nyhan syndrome is a rare genetic disorder that affects primarily males. It is caused by a deficiency in the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT), which is involved in the metabolism of purines, a type of nitrogen-containing base found in DNA and RNA. The symptoms of Lesch-Nyhan syndrome typically begin in early childhood and include self-injurious behavior, such as biting, hitting, and head-banging, as well as intellectual disability, spasticity, and problems with speech and language. Affected individuals also have an increased risk of developing gout, a type of arthritis caused by the buildup of uric acid crystals in the joints. Lesch-Nyhan syndrome is inherited in an X-linked recessive pattern, which means that it is caused by a mutation in the HPRT gene located on the X chromosome. Since males have only one X chromosome, they are more likely to be affected by the disorder than females, who have two X chromosomes and can inherit a normal copy from one parent to compensate for the mutated copy.
Pentosyltransferases are a group of enzymes that transfer a pentose sugar moiety from one molecule to another. In the medical field, pentosyltransferases are important in the metabolism of carbohydrates, nucleic acids, and other biomolecules. They play a role in the synthesis of various compounds, including nucleotides, glycosaminoglycans, and other complex carbohydrates. Pentosyltransferases are also involved in the breakdown of certain molecules, such as heparan sulfate and dermatan sulfate. Mutations in genes encoding pentosyltransferases can lead to various diseases, including mucopolysaccharidoses and other lysosomal storage disorders.
Adenine is a nitrogenous base that is found in DNA and RNA. It is one of the four nitrogenous bases that make up the genetic code, along with guanine, cytosine, and thymine (in DNA) or uracil (in RNA). Adenine is a purine base, which means it has a double ring structure with a six-membered ring fused to a five-membered ring. It is one of the two purine bases found in DNA and RNA, the other being guanine. Adenine is important in the function of DNA and RNA because it forms hydrogen bonds with thymine (in DNA) or uracil (in RNA) to form the base pairs that make up the genetic code.
Xanthines are a group of compounds that include caffeine, theophylline, and theobromine. They are naturally occurring alkaloids found in plants such as coffee, tea, and cocoa. In the medical field, xanthines are used as bronchodilators to treat conditions such as asthma and chronic obstructive pulmonary disease (COPD). They work by relaxing the muscles in the airways, allowing air to flow more easily. Xanthines can also be used to treat heart rhythm disorders and to prevent blood clots. However, they can have side effects such as nausea, vomiting, and increased heart rate, and may interact with other medications.
Purine nucleotides are a type of nucleotide that contains the purine base adenine (A) or guanine (G). They are important components of DNA and RNA, and are involved in various cellular processes such as energy metabolism, DNA synthesis, and gene expression. Purine nucleotides are synthesized from the amino acid glycine and the nucleotide precursor inosine monophosphate (IMP). There are two types of purine nucleotides: purine nucleosides (which contain a sugar and a purine base) and purine nucleotides (which contain a sugar, a phosphate group, and a purine base).
Purine-Nucleoside Phosphorylase (PNP) is an enzyme that plays a crucial role in the metabolism of purine nucleosides, which are the building blocks of DNA and RNA. PNP catalyzes the conversion of purine nucleosides to their corresponding nucleoside monophosphates, which are then used in various metabolic pathways. In the medical field, PNP deficiency is a rare genetic disorder that affects the metabolism of purine nucleosides. This deficiency can lead to the accumulation of toxic levels of purine nucleosides and their breakdown products in the body, which can cause a range of symptoms, including neurological problems, liver damage, and bone marrow failure. PNP deficiency is typically diagnosed through blood tests that measure the activity of the enzyme in the blood and bone marrow. Treatment for PNP deficiency typically involves the use of medications that help to lower the levels of purine nucleosides in the body, such as allopurinol and febuxostat. In severe cases, bone marrow transplantation may be necessary to replace the defective bone marrow cells.
Nucleobase transport proteins, also known as nucleoside transporters, are a group of proteins that are responsible for the transport of nucleobases (the building blocks of nucleic acids) across cell membranes. These proteins play a crucial role in the metabolism of nucleic acids, as they allow cells to take up and utilize nucleobases for the synthesis of DNA and RNA. There are several different types of nucleobase transport proteins, including concentrative nucleoside transporters (CNTs) and equilibrative nucleoside transporters (ENTs). CNTs are responsible for the active transport of nucleobases against a concentration gradient, while ENTs facilitate the passive diffusion of nucleobases down a concentration gradient. Nucleobase transport proteins are found in a wide variety of cell types, including those of the immune system, nervous system, and cardiovascular system. They are also involved in the transport of nucleoside drugs, which are used to treat a variety of conditions, including cancer, viral infections, and autoimmune diseases.
Uric acid is a chemical compound that is produced when the body breaks down purines, which are found in many foods and beverages. It is the main component of uric acid crystals, which can accumulate in the joints and other tissues if levels of uric acid in the blood become too high. This condition is known as gout. Uric acid is also a natural antioxidant that helps protect the body against damage from free radicals. It is excreted from the body through the kidneys in the urine. In the medical field, high levels of uric acid in the blood are often associated with gout, kidney stones, and other health problems. Treatment for high uric acid levels may include lifestyle changes, such as reducing the intake of purine-rich foods and increasing physical activity, as well as medications to lower uric acid levels in the blood.
Guanine is a nitrogenous base that is found in DNA and RNA. It is one of the four nitrogenous bases that make up the genetic code, along with adenine, cytosine, and thymine (in DNA) or uracil (in RNA). Guanine is a purine base, which means it has a double ring structure consisting of a six-membered pyrimidine ring fused to a five-membered imidazole ring. It is one of the two purine bases found in DNA and RNA, the other being adenine. Guanine plays a critical role in the structure and function of DNA and RNA, as it forms hydrogen bonds with cytosine in DNA and with uracil in RNA, which helps to stabilize the double helix structure of these molecules.
Adenine Phosphoribosyltransferase (APRT) is an enzyme that plays a crucial role in the metabolism of purines, which are essential building blocks of DNA and RNA. APRT catalyzes the transfer of a ribose moiety from 5-phosphoribosyl-1-pyrophosphate (PRPP) to adenine, forming AMP (adenosine monophosphate) and PPi (pyrophosphate). In the medical field, APRT deficiency is a rare genetic disorder that results from a deficiency in the APRT enzyme. This deficiency leads to an accumulation of uric acid and its derivatives in the body, which can cause a range of health problems, including kidney stones, gout, and kidney failure. APRT deficiency is typically inherited in an autosomal recessive pattern, meaning that an individual must inherit two copies of the defective gene (one from each parent) to develop the disorder. Diagnosis of APRT deficiency typically involves blood tests to measure uric acid levels and genetic testing to identify mutations in the APRT gene. Treatment for APRT deficiency typically involves lifelong management of uric acid levels through dietary modifications, medications, and, in severe cases, kidney transplantation.
Purine-pyrimidine metabolism is a set of biochemical pathways that are responsible for the synthesis and breakdown of purines and pyrimidines, which are essential components of DNA and RNA. Inborn errors of purine-pyrimidine metabolism refer to genetic disorders that affect the enzymes involved in these pathways, leading to an imbalance in the levels of purines and pyrimidines in the body. This can result in a variety of symptoms, including neurological problems, developmental delays, and organ damage. Inborn errors of purine-pyrimidine metabolism are typically diagnosed through genetic testing and can be treated with dietary restrictions, medications, and in some cases, bone marrow transplantation.
Allopurinol is a medication used to treat gout and prevent kidney stones caused by high levels of uric acid in the blood. It works by inhibiting the production of uric acid in the body, which helps to lower the levels of uric acid in the blood and prevent the formation of uric acid crystals that can cause gout attacks and kidney stones. Allopurinol is typically taken once or twice a day, and the dosage may be adjusted based on the patient's response to the medication and their blood uric acid levels. It is important to note that allopurinol may cause side effects, such as skin rash, nausea, and liver problems, and should be used under the supervision of a healthcare provider.
Thioguanine is an antineoplastic medication that is used to treat certain types of cancer, including acute lymphoblastic leukemia (ALL) and Hodgkin's lymphoma. It works by inhibiting the growth and division of cancer cells. Thioguanine is usually given as a tablet or a liquid to be taken by mouth. It is usually taken once a day, but the dosage and schedule may vary depending on the type and stage of cancer being treated, as well as the patient's overall health. Thioguanine can cause side effects, including nausea, vomiting, diarrhea, loss of appetite, fatigue, and low blood cell counts. It can also cause more serious side effects, such as liver damage, lung problems, and allergic reactions. Therefore, it is important for patients to be closely monitored by their healthcare provider while taking thioguanine.
Adenosine is a naturally occurring nucleoside that plays a crucial role in various physiological processes in the human body. It is a component of the nucleic acids DNA and RNA and is also found in high concentrations in the cells of the heart, brain, and other organs. In the medical field, adenosine is often used as a medication to treat certain heart conditions, such as supraventricular tachycardia (SVT) and atrial fibrillation (AFib). Adenosine works by blocking the electrical signals that cause the heart to beat too fast or irregularly. It is typically administered as an intravenous injection and has a short duration of action, lasting only a few minutes. Adenosine is also used in research to study the function of various cells and tissues in the body, including the nervous system, immune system, and cardiovascular system. It has been shown to have a wide range of effects on cellular signaling pathways, including the regulation of gene expression, cell proliferation, and apoptosis (cell death).
Nucleosides are organic compounds that are composed of a nitrogenous base (either adenine, guanine, cytosine, thymine, uracil, or hypoxanthine) and a pentose sugar (ribose or deoxyribose). They are the building blocks of nucleic acids, such as DNA and RNA, which are essential for the storage and transmission of genetic information in living organisms. In the medical field, nucleosides are often used as components of antiviral and anticancer drugs, as well as in the treatment of certain genetic disorders.
Purine nucleosides are a type of nucleoside that contains a purine base, which is one of two types of nitrogen-containing bases found in DNA and RNA. Purine nucleosides are important components of nucleic acids, which are the building blocks of DNA and RNA. They are also involved in various cellular processes, including energy metabolism and the synthesis of nucleic acids. In the medical field, purine nucleosides are used as medications to treat certain types of cancer and to manage symptoms of certain viral infections. They are also being studied for their potential use in the treatment of other conditions, such as autoimmune diseases and neurological disorders.
Thioinosine is a synthetic nucleoside analog that is used in the treatment of certain viral infections, particularly cytomegalovirus (CMV) retinitis in people with AIDS. It is a prodrug that is converted to its active form, inosine, in the body. Thioinosine is administered intravenously and has been shown to be effective in reducing the frequency and severity of CMV retinitis episodes. It is also being studied for its potential use in the treatment of other viral infections, such as hepatitis B and C.
Adenine nucleotides are a type of nucleotide that contains the nitrogenous base adenine (A) and a sugar-phosphate backbone. They are important molecules in the cell and play a crucial role in various biological processes, including energy metabolism and DNA synthesis. There are three types of adenine nucleotides: adenosine monophosphate (AMP), adenosine diphosphate (ADP), and adenosine triphosphate (ATP). AMP is the simplest form of adenine nucleotide, with only one phosphate group attached to the sugar. ADP has two phosphate groups attached to the sugar, while ATP has three phosphate groups. ATP is often referred to as the "energy currency" of the cell because it stores and releases energy through the transfer of phosphate groups. When ATP is broken down, one of its phosphate groups is released, releasing energy that can be used by the cell for various processes. When ATP is synthesized, energy is required to attach a new phosphate group to the molecule. Adenine nucleotides are involved in many cellular processes, including muscle contraction, nerve impulse transmission, and the synthesis of proteins and nucleic acids. They are also important in the regulation of gene expression and the maintenance of cellular homeostasis.
Xanthine dehydrogenase (XDH) is an enzyme that plays a crucial role in the metabolism of purines, which are nitrogen-containing compounds found in all living cells. XDH catalyzes the conversion of xanthine to uric acid, which is the final product of purine metabolism in humans and many other animals. XDH is a mitochondrial enzyme that is encoded by the XDH gene and is found in many tissues throughout the body, including the liver, kidneys, and intestines. It is also present in red blood cells and is involved in the regulation of oxygen transport. In addition to its role in purine metabolism, XDH has been implicated in a number of other biological processes, including the regulation of energy metabolism, the detoxification of reactive oxygen species, and the maintenance of cellular redox balance. Disruptions in XDH activity can lead to a number of medical conditions, including xanthinuria, which is a rare genetic disorder characterized by the accumulation of xanthine in the blood and urine. Xanthinuria can cause a range of symptoms, including abdominal pain, nausea, and vomiting, and can also lead to the formation of kidney stones.
Allantoin is a naturally occurring organic compound that is found in many plants, including comfrey, poplar, and chicory. It is also synthesized in the body as a byproduct of purine metabolism. In the medical field, allantoin is used as a moisturizing agent and skin protectant. It is commonly found in skin care products, such as creams, lotions, and soaps, and is believed to help soothe dry, itchy, or irritated skin. Allantoin is also used in some wound care products to promote healing and reduce inflammation. In addition to its use in skin care products, allantoin has been studied for its potential therapeutic effects in other medical conditions. For example, it has been shown to have anti-inflammatory and analgesic properties, and may be useful in the treatment of conditions such as rheumatoid arthritis and osteoarthritis. Allantoin has also been studied for its potential to promote wound healing and improve skin regeneration in conditions such as burns and ulcers.
Guanosine monophosphate (GMP) is a nucleotide that plays a crucial role in various cellular processes, including signal transduction, gene expression, and energy metabolism. It is a component of the nucleic acids RNA and DNA and is synthesized from guanosine triphosphate (GTP) by the enzyme guanylate cyclase. In the medical field, GMP is often studied in relation to its role in the regulation of blood pressure, as it is a key mediator of the renin-angiotensin-aldosterone system. GMP also plays a role in the regulation of the immune system and has been implicated in the pathogenesis of various diseases, including cancer, cardiovascular disease, and neurological disorders. In addition, GMP is used as a drug in the treatment of certain conditions, such as erectile dysfunction and pulmonary hypertension. It works by relaxing smooth muscle cells in the blood vessels, which can improve blood flow and reduce blood pressure.
6-Mercaptopurine (6-MP) is a medication that is used to treat certain types of cancer, such as leukemia and lymphoma. It is a type of chemotherapy drug that works by slowing or stopping the growth of cancer cells in the body. 6-MP is usually given in combination with other medications to increase its effectiveness and reduce the risk of side effects. It is usually taken by mouth, although it can also be given by injection. Common side effects of 6-MP include nausea, vomiting, loss of appetite, and low blood cell counts. It is important to closely follow the instructions of your healthcare provider when taking 6-MP, as it can have serious side effects if not used properly.
Nucleoside transport proteins are a group of proteins that are responsible for the transport of nucleosides, which are the building blocks of nucleic acids (DNA and RNA), across cell membranes. These proteins play a crucial role in the metabolism of nucleosides and are involved in various cellular processes, including DNA synthesis, RNA metabolism, and energy production. There are several types of nucleoside transport proteins, including concentrative nucleoside transporters (CNTs), equilibrative nucleoside transporters (ENTs), and nucleoside diphosphate kinases (NDPKs). CNTs are responsible for the active transport of nucleosides against their concentration gradient, while ENTs facilitate the passive diffusion of nucleosides across cell membranes. NDPKs, on the other hand, phosphorylate nucleosides to form nucleoside diphosphates, which are important intermediates in nucleic acid metabolism. Disruptions in the function of nucleoside transport proteins can lead to various diseases, including cancer, viral infections, and neurological disorders. For example, mutations in the CNT gene have been linked to inherited disorders of purine metabolism, such as Lesch-Nyhan syndrome and adenosine deaminase deficiency. Similarly, changes in the expression or function of ENTs have been implicated in the development of certain types of cancer, such as breast and lung cancer.
Uracil is a nitrogenous base that is found in RNA, but not in DNA. It is one of the four nitrogenous bases that make up the RNA molecule, along with adenine, guanine, and cytosine. Uracil is a pyrimidine base, which means that it has a six-membered ring structure with two nitrogen atoms and two carbon atoms. It is important for the function of RNA because it is involved in the process of transcription, in which the genetic information in DNA is copied into RNA. In addition, uracil is also involved in the process of translation, in which the information in RNA is used to synthesize proteins.
Azaserine is a chemical compound that is used as a nitrogen mustard agent in chemotherapy. It is a prodrug that is converted to its active form, mustard gas, in the body. Mustard gas is a toxic chemical that can cause severe skin and lung damage, as well as other health problems. Azaserine is typically used to treat certain types of cancer, such as Hodgkin's lymphoma and non-Hodgkin's lymphoma. It is usually given in combination with other chemotherapy drugs to increase its effectiveness.
Archaeoglobales is a group of Archaea, which are single-celled microorganisms that are not classified as bacteria. They are found in a variety of environments, including hot springs, deep-sea hydrothermal vents, and oil reservoirs. In the medical field, Archaeoglobales are of interest because some species of these microorganisms have the ability to degrade hydrocarbons, such as oil and gas, which makes them potential candidates for bioremediation of oil spills and other environmental pollutants. Additionally, some species of Archaeoglobales have been found to produce bioactive compounds, such as antibiotics and antifungal agents, which could have potential applications in medicine.
In the medical field, ribonucleosides are the building blocks of ribonucleic acid (RNA). They are composed of a nitrogenous base (adenine, guanine, cytosine, or uracil), a five-carbon sugar (ribose), and a phosphate group. There are four types of ribonucleosides: adenosine, guanosine, cytidine, and uridine. These nucleosides are essential for the synthesis of RNA, which plays a crucial role in various cellular processes, including protein synthesis, gene expression, and regulation of cellular metabolism. In addition to their role in RNA synthesis, ribonucleosides have also been found to have therapeutic potential in the treatment of various diseases, including cancer, viral infections, and neurological disorders. For example, some ribonucleosides have been shown to have antiviral activity against HIV and hepatitis C virus, while others have been found to have neuroprotective effects in animal models of neurodegenerative diseases such as Alzheimer's and Parkinson's disease.
Deamination is a biochemical process in which an amino group (-NH2) is removed from an amino acid molecule. This process is important in the metabolism of amino acids, as it allows the body to convert excess amino acids into other compounds that can be used for energy or other metabolic processes. In the medical field, deamination is often used to refer to the breakdown of certain amino acids in the liver, particularly those that are not essential for the body's needs. For example, the liver can convert the amino acid tryptophan into the neurotransmitter serotonin, which plays a role in mood regulation. However, if there is an excess of tryptophan in the body, the liver will convert it into a byproduct called kynurenine, which can be toxic if it accumulates in high levels. Deamination can also be used to refer to the breakdown of nucleic acids, such as DNA and RNA, which contain nitrogenous bases that can be deaminated to form other compounds. This process is important in the regulation of gene expression and the maintenance of cellular function.
Methylthioinosine (MTI) is a purine nucleoside analog that has been used in the treatment of various types of cancer, including leukemia and lymphoma. It works by inhibiting the activity of an enzyme called inosine monophosphate dehydrogenase (IMPDH), which is involved in the synthesis of guanosine nucleotides. By inhibiting IMPDH, MTI can disrupt the growth and proliferation of cancer cells.
Aminopterin is a medication that was originally developed as an antifolate, meaning it inhibits the growth of cells that rely on folic acid for their metabolism. It is used in the treatment of certain types of leukemia and other blood disorders, as well as in the prevention of neural tube defects in pregnant women. Aminopterin works by blocking the enzyme dihydrofolate reductase, which is necessary for the synthesis of folic acid. This leads to a deficiency of folic acid in the cells, which can cause them to die or stop dividing.
Oxypurinol is a medication that is used to treat gout, a type of arthritis that is caused by the buildup of uric acid crystals in the joints. It works by inhibiting the production of uric acid in the body, which helps to reduce the amount of uric acid in the blood and prevent the formation of uric acid crystals. Oxypurinol is typically taken in pill form and is usually prescribed for people who have frequent gout attacks or who have not responded well to other treatments for gout. It may also be used to prevent gout attacks in people who are at high risk of developing the condition.
Adenosine monophosphate (AMP) is a nucleotide that plays a crucial role in various cellular processes, including energy metabolism, signal transduction, and gene expression. It is a component of the nucleic acids DNA and RNA and is synthesized from adenosine triphosphate (ATP) by the removal of two phosphate groups. In the medical field, AMP is often used as a biomarker for cellular energy status and is involved in the regulation of various physiological processes. For example, AMP levels are increased in response to cellular energy depletion, which can trigger the activation of AMP-activated protein kinase (AMPK), a key regulator of energy metabolism. Additionally, AMP is involved in the regulation of the sleep-wake cycle and has been shown to play a role in the development of various neurological disorders, including Alzheimer's disease and Parkinson's disease.
In the medical field, pentosephosphates refer to a group of five-carbon sugars that are intermediates in the pentose phosphate pathway (PPP), a metabolic pathway that occurs in the cytosol of cells. The PPP is involved in the production of NADPH, a coenzyme that is important for the reduction of molecules such as oxygen and glutathione, as well as the synthesis of nucleotides, amino acids, and other biomolecules. Pentosephosphates are also involved in the regulation of glucose metabolism and the production of energy. In particular, the PPP provides a source of reducing power (in the form of NADPH) for the synthesis of fatty acids and cholesterol, and it also generates ATP through substrate-level phosphorylation. Disruptions in the pentose phosphate pathway can lead to a variety of medical conditions, including diabetes, cancer, and neurodegenerative diseases. For example, mutations in genes encoding enzymes involved in the PPP have been linked to inherited disorders such as hereditary fructose intolerance and glucose-6-phosphate dehydrogenase deficiency.
Guanosine is a nucleoside that is composed of the nitrogenous base guanine and the sugar ribose. It is a building block of nucleic acids, such as DNA and RNA, and plays a crucial role in various cellular processes. In the medical field, guanosine is used as a medication to treat certain types of cancer, such as acute myeloid leukemia and non-Hodgkin's lymphoma. It works by inhibiting the growth and proliferation of cancer cells. Guanosine is also used as a supplement to support immune function and to treat certain viral infections, such as cytomegalovirus (CMV) and herpes simplex virus (HSV). It is believed to work by stimulating the production of immune cells and by inhibiting the replication of viruses. In addition, guanosine is involved in the regulation of various cellular processes, such as gene expression, signal transduction, and energy metabolism. It is also a precursor of the nucleotide guanosine triphosphate (GTP), which plays a key role in many cellular processes, including protein synthesis and cell division.
Dipyridamole is a medication that is used to prevent blood clots from forming in the blood vessels. It is also used to treat angina (chest pain caused by reduced blood flow to the heart) and to prevent blood clots after a heart attack or stroke. Dipyridamole works by increasing the amount of a substance called prostacyclin in the blood vessels, which helps to keep the blood vessels open and improve blood flow. It is usually taken by mouth in the form of a tablet or capsule.
Coformycin is an antibiotic medication that is used to treat a variety of bacterial infections. It is a member of the aminoglycoside class of antibiotics, which work by binding to bacterial ribosomes and inhibiting protein synthesis. Coformycin is typically used to treat infections of the respiratory tract, urinary tract, and skin. It is usually administered intravenously, although it can also be given intramuscularly or orally in some cases. Side effects of coformycin may include nausea, vomiting, diarrhea, and hearing loss. It is important to note that coformycin can be toxic to the kidneys, so it should be used with caution in patients with kidney disease.
N-Glycosyl Hydrolases (NGHs) are a group of enzymes that hydrolyze (break down) the glycosidic bonds in complex carbohydrates, also known as glycans. These enzymes play important roles in various biological processes, including cell signaling, protein folding, and immune response. In the medical field, NGHs are of particular interest due to their involvement in diseases such as cancer, diabetes, and infectious diseases. For example, some NGHs are overexpressed in cancer cells, leading to increased cell proliferation and invasion. In diabetes, NGHs are involved in the breakdown of glycans in the body, which can lead to hyperglycemia (high blood sugar levels). In infectious diseases, NGHs are produced by pathogens to evade the host immune system. NGHs are also being studied as potential therapeutic targets for various diseases. For example, inhibitors of NGHs have been developed as potential treatments for cancer and diabetes. Additionally, NGHs are being investigated as potential biomarkers for disease diagnosis and prognosis.
High-pressure liquid chromatography (HPLC) is a technique used in the medical field to separate and analyze complex mixtures of compounds. It involves the use of a liquid mobile phase that is forced through a column packed with a stationary phase under high pressure. The compounds in the mixture interact with the stationary phase to different extents, causing them to separate as they pass through the column. The separated compounds are then detected and quantified using a detector, such as a UV detector or a mass spectrometer. HPLC is commonly used in the analysis of drugs, biological samples, and other complex mixtures in the medical field.
DNA glycosylases are a class of enzymes that play a crucial role in the repair of damaged DNA. These enzymes recognize and remove damaged or inappropriate nucleotides from the DNA strand, creating an abasic site (also known as an AP site) that can be further processed by other DNA repair enzymes. There are several types of DNA glycosylases, each with a specific substrate specificity. For example, some DNA glycosylases recognize and remove damaged bases such as thymine glycol, 8-oxoguanine, and uracil, while others recognize and remove bulky adducts such as benzo[a]pyrene diol epoxide. DNA glycosylases are important for maintaining the integrity of the genome and preventing mutations that can lead to cancer and other diseases. Mutations in DNA glycosylase genes have been linked to an increased risk of certain types of cancer, such as colon cancer and lung cancer.
Thymidine is a nucleoside that is a building block of DNA and RNA. It is composed of a deoxyribose sugar molecule and a thymine base. Thymidine is an essential component of DNA and is involved in the replication and transcription of genetic material. It is also a precursor to the synthesis of thymine triphosphate (dTTP), which is a nucleotide used in DNA and RNA synthesis. In the medical field, thymidine is used as a diagnostic tool to detect and measure the activity of certain enzymes involved in DNA synthesis, and it is also used as a component of certain antiviral drugs.
Guanine nucleotides are a type of nucleotide that contains the nitrogenous base guanine. They are important components of DNA and RNA, which are the genetic material of all living organisms. In DNA, guanine nucleotides are paired with cytosine nucleotides to form the base pair G-C, which is one of the four possible base pairs in DNA. In RNA, guanine nucleotides are paired with uracil nucleotides to form the base pair G-U. Guanine nucleotides play a crucial role in the structure and function of DNA and RNA, and are involved in many important biological processes, including gene expression, DNA replication, and protein synthesis.
Adenosine deaminase inhibitors (ADIs) are a class of drugs that inhibit the activity of the enzyme adenosine deaminase (ADA). This enzyme plays a crucial role in the metabolism of adenosine, a naturally occurring nucleoside in the body. In individuals with certain genetic disorders, such as severe combined immunodeficiency (SCID) or immunodeficiency with hyper-IgM syndrome (IHPS), the activity of ADA is impaired, leading to a buildup of toxic levels of adenosine in the body. ADIs work by inhibiting the activity of ADA, which allows for the accumulation of adenosine in the body. This accumulation of adenosine can have a number of beneficial effects, including the stimulation of immune cell proliferation and activation, which can help to improve the immune function of individuals with SCID or IHPS. There are several different ADIs that have been developed for the treatment of these genetic disorders, including azathioprine, mercaptopurine, and cladribine. These drugs are typically administered orally and are generally well-tolerated, although they can cause side effects such as nausea, vomiting, and an increased risk of infection.
Adenylosuccinate synthase (ADSS) is an enzyme that plays a crucial role in the biosynthesis of the nucleotide adenylate. It catalyzes the conversion of adenosine monophosphate (AMP) and succinyl-CoA to adenylosuccinate (AMP-S-CoA), which is a precursor for the synthesis of several important nucleotides, including guanosine triphosphate (GTP) and inosine triphosphate (ITP). ADSS is a highly conserved enzyme that is found in all organisms, from bacteria to humans. It is encoded by the ADSS gene, which is located on chromosome 17 in humans. In the medical field, ADSS is of interest because it is involved in the metabolism of purines, which are the building blocks of nucleotides. Mutations in the ADSS gene can lead to a rare inherited disorder called adenylosuccinate synthase deficiency (ASSD), which is characterized by a deficiency in ADSS enzyme activity and a buildup of AMP-S-CoA in the body. This can lead to a range of symptoms, including developmental delays, seizures, and intellectual disability. Treatment for ASSD typically involves dietary modifications and supplementation with nucleotides.
Aminohydrolases are a class of enzymes that catalyze the hydrolysis of amine-containing substrates, breaking down the amine group and releasing a water molecule. These enzymes are involved in a wide range of biological processes, including the metabolism of amino acids, neurotransmitters, and other compounds. In the medical field, aminohydrolases are often used as diagnostic tools to identify specific diseases or conditions. For example, the enzyme creatine kinase (CK) is a aminohydrolase that is released into the bloodstream in response to muscle damage, and elevated levels of CK can indicate muscle injury or disease. Similarly, the enzyme alanine aminotransferase (ALT) is a aminohydrolase that is released into the bloodstream in response to liver damage, and elevated levels of ALT can indicate liver disease. Aminohydrolases are also used in the development of new drugs and therapies. For example, some drugs target specific aminohydrolases to treat conditions such as depression, anxiety, and Alzheimer's disease. Additionally, aminohydrolases are being studied as potential targets for cancer therapy, as some tumors overexpress certain aminohydrolases, making them vulnerable to inhibition by targeted drugs.
Ribose-5-phosphate (R5P) is a monosaccharide that is a key intermediate in the pentose phosphate pathway (PPP), which is a metabolic pathway that generates ribose-5-phosphate, NADPH, and ATP. In the medical field, ribose-5-phosphate is important for the production of nucleotides, which are the building blocks of DNA and RNA. It is also involved in the synthesis of other important biomolecules, such as coenzyme A and heme. Deficiencies in the enzymes involved in the PPP can lead to a variety of medical conditions, including anemia, neurological disorders, and skin disorders.
DNA, or deoxyribonucleic acid, is a molecule that carries genetic information in living organisms. It is composed of four types of nitrogen-containing molecules called nucleotides, which are arranged in a specific sequence to form the genetic code. In the medical field, DNA is often studied as a tool for understanding and diagnosing genetic disorders. Genetic disorders are caused by changes in the DNA sequence that can affect the function of genes, leading to a variety of health problems. By analyzing DNA, doctors and researchers can identify specific genetic mutations that may be responsible for a particular disorder, and develop targeted treatments or therapies to address the underlying cause of the condition. DNA is also used in forensic science to identify individuals based on their unique genetic fingerprint. This is because each person's DNA sequence is unique, and can be used to distinguish one individual from another. DNA analysis is also used in criminal investigations to help solve crimes by linking DNA evidence to suspects or victims.
Pyrimidine nucleotides are a type of nucleotide that contains a pyrimidine base, which is one of the two types of nitrogenous bases found in DNA and RNA. Pyrimidine nucleotides are important components of nucleic acids, which are the building blocks of DNA and RNA. There are two types of pyrimidine nucleotides: cytosine (C), which is found in both DNA and RNA, and thymine (T), which is found only in DNA. Pyrimidine nucleotides are synthesized in the body from the amino acid aspartate and the vitamin B9 (folate). They play a crucial role in the synthesis of DNA and RNA, as well as in the metabolism of amino acids and the production of energy. Pyrimidine nucleotides are also important for the proper functioning of the immune system and the maintenance of healthy skin, hair, and nails.
Tubercidin is an antitubercular drug that was first isolated from the Chinese herb Sophora flavescens. It is a purine nucleoside analog that inhibits the growth of Mycobacterium tuberculosis, the causative agent of tuberculosis. Tubercidin is not commonly used as a first-line treatment for tuberculosis due to its toxicity and potential for drug resistance. However, it has been used in combination with other antitubercular drugs to treat drug-resistant tuberculosis. In addition to its antitubercular activity, tubercidin has also been shown to have antiviral and antifungal properties. It has been studied for its potential use in the treatment of viral infections such as influenza and herpes simplex virus, as well as fungal infections such as candidiasis.
Dilazep is a brand name for the medication diltiazem, which is a calcium channel blocker. Calcium channel blockers are a type of medication that is used to treat high blood pressure, chest pain (angina), and certain heart rhythm disorders. They work by relaxing the muscles in blood vessels, which allows blood to flow more easily and reduces blood pressure. Dilazep is available in both oral tablet and extended-release capsule forms. It is usually taken once or twice a day, with or without food. Dilazep can cause side effects such as headache, dizziness, and constipation. It is important to follow the instructions of your healthcare provider when taking Dilazep.
In the medical field, a cell line refers to a group of cells that have been derived from a single parent cell and have the ability to divide and grow indefinitely in culture. These cells are typically grown in a laboratory setting and are used for research purposes, such as studying the effects of drugs or investigating the underlying mechanisms of diseases. Cell lines are often derived from cancerous cells, as these cells tend to divide and grow more rapidly than normal cells. However, they can also be derived from normal cells, such as fibroblasts or epithelial cells. Cell lines are characterized by their unique genetic makeup, which can be used to identify them and compare them to other cell lines. Because cell lines can be grown in large quantities and are relatively easy to maintain, they are a valuable tool in medical research. They allow researchers to study the effects of drugs and other treatments on specific cell types, and to investigate the underlying mechanisms of diseases at the cellular level.
Phosphoglycerate kinase (PGK) is an enzyme that plays a crucial role in cellular metabolism. It is a key enzyme in the glycolytic pathway, which is the process by which cells convert glucose into energy in the form of ATP (adenosine triphosphate). PGK catalyzes the transfer of a phosphate group from ATP to 1,3-bisphosphoglycerate (1,3-BPG), a molecule that is produced during the earlier stages of glycolysis. This reaction generates 3-phosphoglycerate (3-PGA), which is a key intermediate in the glycolytic pathway. PGK is found in all living cells and is essential for the production of ATP, which is the primary source of energy for cellular processes. In addition to its role in glycolysis, PGK has been implicated in a number of other cellular processes, including the regulation of gene expression and the maintenance of red blood cell shape. In the medical field, PGK is sometimes used as a diagnostic marker for certain diseases, such as cancer and diabetes. Abnormal levels of PGK in the blood or other bodily fluids can be an indication of these conditions. Additionally, PGK is being studied as a potential therapeutic target for the treatment of various diseases, including cancer and heart disease.
Adenosine kinase (AK) is an enzyme that plays a crucial role in the metabolism of adenosine, a purine nucleoside that is involved in various physiological processes, including neurotransmission, vasodilation, and immune function. AK catalyzes the conversion of adenosine to AMP (adenosine monophosphate) and ATP (adenosine triphosphate), which are essential energy sources for cells. This reaction is reversible, and AK can also convert AMP and ATP back to adenosine under certain conditions. In the medical field, AK is of interest because it is involved in several diseases and conditions, including cancer, cardiovascular disease, and neurological disorders. For example, AK has been shown to be overexpressed in some types of cancer, and its inhibition has been proposed as a potential therapeutic strategy. Additionally, AK has been implicated in the development of heart failure and stroke, and its activity has been shown to be modulated by various drugs and environmental factors.
In the medical field, nucleotides are the building blocks of nucleic acids, which are the genetic material of cells. Nucleotides are composed of three components: a nitrogenous base, a pentose sugar, and a phosphate group. There are four nitrogenous bases in DNA: adenine (A), thymine (T), cytosine (C), and guanine (G). There are also four nitrogenous bases in RNA: adenine (A), uracil (U), cytosine (C), and guanine (G). The sequence of these nitrogenous bases determines the genetic information encoded in DNA and RNA.
Amidophosphoribosyltransferase (APRT) is an enzyme that plays a crucial role in the biosynthesis of purines, which are essential building blocks of DNA and RNA. APRT catalyzes the transfer of an amino group from glutamine to 5-phosphoribosyl-1-pyrophosphate (PRPP), a key intermediate in the purine biosynthetic pathway. This reaction generates 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), which is further converted to the purine nucleotides adenosine monophosphate (AMP) and guanosine monophosphate (GMP). Mutations in the APRT gene can lead to a deficiency in APRT activity, resulting in a rare genetic disorder called Lesch-Nyhan syndrome (LNS). LNS is characterized by high levels of uric acid in the blood and urine, as well as neurological symptoms such as self-mutilation and intellectual disability. APRT deficiency can also cause a milder form of the disorder called Lesch-Nyhan variant (LNV), which is characterized by mild to moderate neurological symptoms and high uric acid levels.
Gout is a type of inflammatory arthritis that occurs when uric acid crystals accumulate in the joints, causing pain, swelling, and redness. It is a common condition that affects primarily middle-aged men, although it can also occur in women and children. Gout is caused by the buildup of uric acid in the blood, which can be due to genetics, lifestyle factors, or certain medical conditions. The most common joint affected by gout is the big toe, but it can also affect other joints such as the ankle, knee, wrist, and elbow. Treatment for gout typically involves medications to reduce inflammation and pain, as well as lifestyle changes to lower uric acid levels in the blood.
Resumption of meiosis
Chinese hamster ovary cell
Nucleic acid sequence
Nucleic acid tertiary structure
Nucleic acid analogue
Hypoxanthine - Wikipedia
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- Hypoxanthine-Guanine Phosphoribosyl-Transferase Deficiency: Avoid use of mycophenolate mofetil. (nih.gov)
- Duan J, Nilsson L, Lambert B. Structural and functional analysis of mutations at the human hypoxanthine phosphoribosyl transferase (HPRT1) locus. (medlineplus.gov)
- Lesch-Nyhan syndrome is caused by the deficiency of the enzyme hypoxanthine-guanine phosphoribosyl transferase (HGPRT). (carrieradda.com)
- Human T cell recognition of the blood stage antigen Plasmodium hypoxanthine guanine xanthine phosphoribosyl transferase (HGXPRT) in acute malaria. (ox.ac.uk)
- BACKGROUND: The Plasmodium purine salvage enzyme, hypoxanthine guanine xanthine phosphoribosyl transferase (HGXPRT) can protect mice against Plasmodium yoelii pRBC challenge in a T cell-dependent manner and has, therefore, been proposed as a novel vaccine candidate. (ox.ac.uk)
- Hypoxanthine is converted to xanthine in the liver and it is converted to uric acid by xanthine oxidase. (standardofcare.com)
- Simultaneous Determination of Adenosine, Inosine, Hypoxanthine, Xanthine, and Uric Acid in Microdialysis Samples Using Microbore Column High-Performance Liquid Chromat. (doximity.com)
- The explanation: HGPRT deficient cells in the medium containing all three hypoxanthine, thymidine and aminopterin. (carrieradda.com)
- This medium does not contain hypoxanthine or thymidine to allow for its use with dihydrofolate reductase (DHFR) gene amplification systems. (sigmaaldrich.com)
- The Antibody Hybridoma Core utilizes the fusion partner cell line FOX-NY, a nonimmunoglobulin-secreting myeloma cell line that is hypoxanthine-aminopterin-thymidine (HAT) sensitive. (mayo.edu)
- Also oxidizes hypoxanthine, some other purines and pterins, and aldehydes, but is distinct from EC 184.108.40.206 . (expasy.org)
- Complete deficiency of hypoxanthine-guanine phosphoribosyltransferase (HPRT) activity causes Lesch Nyhan disease (LND), characterized by hyperuricemia, severe action dystonia, choreoathetosis, ballismus, cognitive and attention deficit and self-injurious behavior. (nih.gov)
- A review of the molecular basis of hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency. (medlineplus.gov)
- HPRT deficiency results in failure of the salvage pathway for hypoxanthine and guanine. (msdmanuals.com)
- The crystal structure of human hypoxanthine-guanine phosphoribosyltransferase with bound GMP. (nih.gov)
- HPRT1 gene mutations that cause Lesch-Nyhan syndrome result in a severe shortage (deficiency) or complete absence of hypoxanthine phosphoribosyltransferase 1. (nih.gov)
- For unknown reasons, a deficiency of hypoxanthine phosphoribosyltransferase 1 is associated with low levels of a chemical messenger in the brain called dopamine . (nih.gov)
- Characterization of in vivo somatic mutations at the hypoxanthine phosphoribosyltransferase gene of a human control population. (nih.gov)
- Phenol and 1-naphthol, products of benzene and naphthalene biotransformation, are metabolized during O2- generation by xanthine oxidase/hypoxanthine and phorbol myristate acetate (PMA)-stimulated human neutrophils. (nih.gov)
- Individuals with this condition have lower than normal levels of hypoxanthine phosphoribosyltransferase 1. (medlineplus.gov)