HomocysteineBiosynthesisSynthaseMethylationTrans-sulfuration pathwayMetabolitesGlutathioneEnzyme cystathionineBeta-lyaseLyaseSerineHydrogen sulfideAcid metabolismDeficiencyEnzymes involvedParticipatesCellularGlycineHepaticBacteriaMethanethiolAmino acidsSynthesisAdditionallyMetabolic pathwayProteinVitaminBiochemicalNitrogenResiduesHomocystinuriaGlucoseFattyOrganicAspartateCofactorRatsUtilizationCycleDisorderNutritionalToxicConsumptionForm
Homocysteine29
- Cystathionine beta-lyase (EC 4.4.1.8), also commonly referred to as CBL or β-cystathionase, is an enzyme that primarily catalyzes the following α,β-elimination reaction Thus, the substrate of this enzyme is L-cystathionine, whereas its 3 products are homocysteine, pyruvate, and ammonia. (wikipedia.org)
- Found in plants, bacteria, and yeast, cystathionine beta-lyase is an essential part of the methionine biosynthesis pathway as homocysteine can be directly converted into methionine by methionine synthase. (wikipedia.org)
- Homocystinuria is a disorder of methionine metabolism, leading to an abnormal accumulation of homocysteine and its metabolites (homocystine, homocysteine-cysteine complex, and others) in blood and urine. (medscape.com)
- The accumulation of homocysteine and its metabolites is caused by disruption of any of the 3 interrelated pathways of methionine metabolism-deficiency in the cystathionine B-synthase (CBS) enzyme, defective methylcobalamin synthesis, or abnormality in methylene tetrahydrofolate reductase (MTHFR). (medscape.com)
- Conversion of homocysteine back to methionine, catalyzed by MTHFR and methylcobalamin, is termed the remethylation pathway. (medscape.com)
- Cystathionine β-synthase (CBS) is a key regulator of sulfur amino acid metabolism, taking homocysteine from the methionine cycle to the biosynthesis of cysteine via the trans-sulfuration pathway. (rhea-db.org)
- This study was aimed at investigating the effects of quercetin on mRNA expression and activity of critical enzymes in homocysteine metabolism in rats fed a methionine-enriched diet. (hindawi.com)
- Serum homocysteine was significantly increased after methionine treatment and decreased after the addition of quercetin. (hindawi.com)
- It is concluded that quercetin reduces serum homocysteine by increasing remethylation and transsulfuration of homocysteine in rats exposed to a methionine-enriched diet. (hindawi.com)
- Homocysteine (Hcy) is a nonprotein amino acid, derived from methionine (Met) metabolism [ 1 ]. (hindawi.com)
- In remethylation pathway, Hcy can be remethylated to form Met via methionine synthase (MS) or betaine-homocysteine methyltransferase (BHMT), in which cofactors such as folic acid and vitamin B 12 or betaine are required. (hindawi.com)
- Two other interrelated pathways of methionine metabolism can produce accumulation of homocysteine and its metabolites: defective methylcobalamin synthesis (homocystinuria II) and abnormality in MTHFR (homocystinuria III). (mhmedical.com)
- P-methionine elevated in blood (up to 2 mmol/L). Homocysteine, mixed disulfide, and other sulfur-containing compounds may be present (homocysteine binds to plasma proteins by disulfide bonds). (mhmedical.com)
- The presence of increased amounts of methionine in the cerebrospinal fluid (CSF) (homocysteine may be present) has been reported. (mhmedical.com)
- Essentially, CBS links the two pathways together, through its conversion of homocysteine into cystathionine. (metabolichealing.com)
- Through the CBS enzyme reaction, the substrate that is generated from homocysteine is cystathionine. (metabolichealing.com)
- Although alterations in the methionine metabolism cycle (MMC) have been associated with vascular complications of diabetes, there have not been consistent results about the levels of methionine and homocysteine in type 2 diabetes mellitus (T2DM). (biomedcentral.com)
- The aim of the current study was to predict changes in plasma methionine and homocysteine concentrations after simulated consumption of methionine-rich foods, following the development of a mathematical model for MMC in Zucker Diabetic Fatty (ZDF) rats, as a representative T2DM animal model. (biomedcentral.com)
- Conversion of S-adenosyl-L-homocysteine (SAH) to homocysteine increased and the metabolism of homocysteine was reduced under diabetic conditions, and consequently homocysteine accumulated in the elimination phase. (biomedcentral.com)
- Using our model, we performed simulations to compare the changes in plasma methionine and homocysteine concentrations between ZDF and normal rats, by multiple administrations of the methionine-rich diet of 1 mmol/kg, daily for 60 days. (biomedcentral.com)
- The levels of methionine and homocysteine were elevated approximately two- and three-fold, respectively, in ZDF rats, while there were no changes observed in the normal control rats. (biomedcentral.com)
- These results can be interpreted to mean that both methionine and homocysteine will accumulate in patients with T2DM, who regularly consume high-methionine foods. (biomedcentral.com)
- As a universal key intermediate in the MMC, homocysteine is not obtained from the diet, but is remethylated to methionine, or converted to cysteine by the trans-sulfuration pathway. (biomedcentral.com)
- Here, we focused on the fact that a high-fat diet affects the metabolism of both methionine and homocysteine in a diabetic rat model [ 14 ]. (biomedcentral.com)
- Thus, 0we hypothesized that long-term administration of a high-methionine diet to T2DM rats with normal renal function may create metabolic changes, culminating in an elevated level of circulating homocysteine. (biomedcentral.com)
- To verify this hypothesis, mathematical modeling of methionine metabolism was required to predict the levels of homocysteine derived from given amounts of methionine. (biomedcentral.com)
- The results obtained support the concept that cystathionine serves as a precursor of methionine via the intermediate formation of homocysteine. (rhumbarlv.com)
- Under such metabolic stress conditions, supplies of L-cysteine for glutathione synthesis become limiting, so homocysteine is diverted from the transmethylation pathway (which forms methionine) into the transsulfuration pathway (which forms cystathionine). (pathbank.org)
- If homocysteine is found to drop below normal, he takes this as an indication that methionine is low and must be added. (phoenixrising.me)
Biosynthesis8
- The many biochemical reactions catalyzed by PLP-dependent enzymes are involved in essential biological processes, such as hemoglobin and amino acid biosynthesis, as well as fatty acid metabolism . (oregonstate.edu)
- More specifically, CBS activates the sulfuration process, the biosynthesis of the sulfur-containing amino acid cysteine, and the fate of residual sulfur byproducts through various downstream processes. (metabolichealing.com)
- Methionine: Biosynthesis, Chemical Structure and Toxicity Kamata S,Ishii I Protective roles of transsulfuration against methionine toxicity. (shoyaku.ac.jp)
- What is methionine biosynthesis? (rhumbarlv.com)
- In plants and microorganisms, methionine biosynthesis belongs to the aspartate family, along with threonine and lysine (via diaminopimelate, but not via α-aminoadipate). (rhumbarlv.com)
- Why is the biosynthesis of methionine important to plants? (rhumbarlv.com)
- How is AdoMet used in the biosynthesis of methionine? (rhumbarlv.com)
- Reconstructed carbon and sulfur metabolic pathways, coupled with RNA-Seq analysis, suggested a marginal Crabtree effect under high glucose and activation of sulfur metabolism toward methionine biosynthesis under sulfur limitation in this yeast. (biomedcentral.com)
Synthase11
- Other members include cystathionine gamma-synthase, cystathionine gamma-lyase, and methionine gamma lyase. (wikipedia.org)
- Crystal Structures of Cystathionine beta-Synthase from Saccharomyces cerevisiae: One Enzymatic Step at a Time. (rhea-db.org)
- The mRNA expression of methionine synthase was significantly increased after methionine or methionine plus quercetin supplementation, while its enzymatic activity was significantly increased after methionine plus quercetin supplementation. (hindawi.com)
- The mRNA expression and enzymatic activity of cystathionine β -synthase and cystathionine γ -lyase were upregulated after quercetin, methionine, or quercetin plus methionine treatment and a more significant increase was observed for hepatic cystathionine β -synthase in the methionine plus quercetin treated rats, suggesting an interaction between methionine and quercetin. (hindawi.com)
- In transsulfuration pathway, Hcy is reacted with serine (Ser) to form cystathionine via vitamin B 6 -dependent cystathionine β -synthase (CBS). (hindawi.com)
- Deficiency of cystathionine synthase (homocystinuria I) leads to a failure of transsulfuration of precursors of cysteine, an important component of collagen. (mhmedical.com)
- It is caused by the deficiency of the enzyme cystathionine beta synthase, and the deficiency of folic acid, vitamin B 12 and pyridoxine (vitamin B 6 ), or mutations of related enzymes. (mhmedical.com)
- In that article I discussed how there appears to be two differing perspectives on the nature of CBS (cystathionine beta synthase) gene mutations: the literature's contention of "down-regulated" CBS enzyme activity among carriers of certain mutations, and certain empirical, clinical observations of the opposite situation, specifically that certain CBS gene mutations can cause an "up-regulation" to enzyme activity. (metabolichealing.com)
- This article is a follow-up, based upon my own current hypotheses as well as literature-cited observations regarding these complex yet seemingly critical discussions regarding CBS (cystathionine beta synthase) and the transsulfuration pathway. (metabolichealing.com)
- In plants, this reaction is catalyzed by a cobalamin-independent methionine synthase (EC 2.1. (rhumbarlv.com)
- Thus, methionine synthase not only catalyzes the last reaction in de novo methionine synthesis but also serves to regenerate the methyl group of AdoMet. (rhumbarlv.com)
Methylation2
- Homocystinuria is an autosomal recessively inherited defect in the transsulfuration pathway (homocystinuria I) or methylation pathway (homocystinuria II and III). (medscape.com)
- T helper cells import the amino acid methionine to synthesize new proteins and to provide the methyl groups needed for the methylation of RNA and DNA that drives T cell proliferation and differentiation. (rhumbarlv.com)
Trans-sulfuration pathway1
- The trans-sulfuration pathway is well-conserved in eukaryotes, but the analogous enzymes have different enzymatic behavior in different organisms. (rhea-db.org)
Metabolites2
- Zinc exposure also resulted in decreases in concentrations of the amine containing metabolites, lanthionine, methionine and cystathionine, and an increase in metallothionein gene expression. (bvsalud.org)
- As a result of sulfur metabolism, a number of intermediate metabolites are produced downstream of CBS. (metabolichealing.com)
Glutathione6
- Additionally, given the consistent and large effective size, glutathione metabolism biomarkers have the potential to inform early diagnosis of ASD. (nature.com)
- During general alcohol metabolism, hepatocytes generate mitochondria- and cytochrome P450 2E1 (CYP2E1)-mediated reactive oxygen species (ROS) whose accumulation elicits activation of the hepatic anti-oxidant system, including glutathione (GSH). (e-cmh.org)
- Cysteine is the sulfur-containing amino acid that performs some critical functions in the body, including the formation of thiol-bearing antioxidants such as glutathione and metallothionein. (metabolichealing.com)
- alpha-Ketobutyrate is produced by amino acid catabolism (threonine and methionine) and glutathione anabolism (cysteine formation pathway) and is metabolized to propionyl-CoA and carbon dioxide (PMID: 20526369). (pathbank.org)
- 2-Hydroxybutyrate is released as a byproduct when cystathionine is cleaved into cysteine that is incorporated into glutathione. (pathbank.org)
- In particular, he has recognized the importance of glutathione in the metabolism of vitamin B12. (phoenixrising.me)
Enzyme cystathionine1
- In addition, L-cysteine can be converted into hydrogen sulfide and pyruvic acid through the action of the enzyme cystathionine gamma-lyase. (cannabisdatabase.ca)
Beta-lyase3
- Cystathionine beta-lyase is a tetramer composed of identical subunits, and is constructed as a dimer of dimers, each associated with one molecule of PLP bound to the catalytic site by a lysine residue. (wikipedia.org)
- The cystathionine beta-lyase monomer consists of three functionally and structurally distinct domains: Composed of three α-helices and one beta-strand that contribute to the formation of the quaternary structure. (wikipedia.org)
- As shown in the mechanism below, cystathionine beta-lyase facilitates the S-C bond cleavage in cystathionine with the use of a PLP cofactor bounded to a catalytic lysine residue. (wikipedia.org)
Lyase2
- Subsequently, cystathionine is hydrolyzed to yield cysteine (Cys) and α -ketobutyrate via vitamin B 6 -dependent cystathionine γ -lyase (CSE) and finally to taurine (Tau) [ 2 , 3 ]. (hindawi.com)
- H2S is biosynthesized from two enzymes: CBS and CTH (cystathionine gamma lyase), with P5P as the cofactor. (metabolichealing.com)
Serine1
- 2-Ketobutyric acid is a substance that is involved in the metabolism of many amino acids (glycine, methionine, valine, leucine, serine, threonine, isoleucine) as well as propanoate metabolism and C-5 branched dibasic acid metabolism. (pathbank.org)
Hydrogen sulfide1
- The main backbone is derived from aspartic acid, while the sulfur may come from cysteine, methanethiol, or hydrogen sulfide. (rhumbarlv.com)
Acid metabolism2
- This enzyme participates in 5 metabolic pathways: methionine metabolism, cysteine metabolism, selenoamino acid metabolism, nitrogen metabolism, and sulfur metabolism. (wikipedia.org)
- These include reactions of cellular respiration, the release of glucose stores, and amino acid metabolism. (mskcc.org)
Deficiency2
- However, chronic alcohol consumption decreases GSH generation through cysteine deficiency by suppressing the methionine cycle and trans-sulfuration system, whereas it turns on an alternative defense pathway, such as the xCT transporter, to compensate for GSH shortage. (e-cmh.org)
- 2-Hydroxybutyric acid generally appears at high concentrations in situations related to deficient energy metabolism (e.g. birth asphyxia) and also in inherited metabolic diseases affecting the central nervous system during neonatal development, such as "cerebral" lactic acidosis, glutaric aciduria type II, dihydrolipoyl dehydrogenase (E3) deficiency, and propionic acidemia. (pathbank.org)
Enzymes involved2
- Most of the enzyme's catalytic site residues are conserved amongst the enzymes involved in the transsulfuration pathway. (wikipedia.org)
- And they are indications of vitamin and mineral co-factor needs because of the enzymes involved in those pathways. (drweitz.com)
Participates1
- Within humans, L-cysteine participates in a number of enzymatic reactions. (cannabisdatabase.ca)
Cellular2
- Because of this central role in cellular metabolism, a precise knowledge of the biosynthetic pathways that are responsible for homeostatic regulation of methionine and AdoMet in plants has practical implications, particularly in herbicide design. (rhumbarlv.com)
- The elucidation and description of the molecular and structural features of gasotransmitters, their production pathways, signaling mechanisms, cellular and molecular targets, and functional impact in prokaryotic and eukaryotic cells are the focus of this book. (rsc.org)
Glycine1
- Cysteine and derivatives are compounds containing cysteine or a derivative thereof resulting from reaction of cysteine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom. (cannabisdatabase.ca)
Hepatic2
- Meanwhile, hepatic ratio of S-adenosylmethionine to S-adenosylhomocysteine was significantly decreased in response to methionine supplementation and normalized after the addition of quercetin. (hindawi.com)
- In addition, we address different responses of alcohol metabolism that are specific to hepatic zones ( Fig. 1 ). (e-cmh.org)
Bacteria2
- Some bacteria can synthesize methionine using organic sulfur through transsulfuration of O-succinyl-L-homoserine with L-cysteine to form L-cystathionine. (rhumbarlv.com)
- L-Cysteine exists in all living species, ranging from bacteria to humans. (cannabisdatabase.ca)
Methanethiol1
- Methanethiol (CH3 SH) - Is an organosulfur compound derived from cysteine oxidation. (metabolichealing.com)
Amino acids1
- L-methionine (Met) is one of the proteinogenic amino acids. (rhumbarlv.com)
Synthesis4
- How do you synthesis methionine? (rhumbarlv.com)
- The terminal step in methionine synthesis involves the transfer of the methyl group from N5-methyl-tetrahydrofolate (5-CH3H4PteGlun) to Hcy (Fig. 1). (rhumbarlv.com)
- Consequently, methionine is the first amino acid to dock in the ribosome during the synthesis of proteins. (rhumbarlv.com)
- What is the role of methionine in protein synthesis? (rhumbarlv.com)
Additionally1
- Additionally, l-cysteine has been implicated as an "excitotoxin" in numerous studies, where it has been shown as an initiator of neuron cell death via glutamate's NMDA receptor (5). (metabolichealing.com)
Metabolic pathway2
- 1, 3-Diaminopropane is involved in the arginine/proline metabolic pathways and the beta-alanine metabolic pathway. (pathbank.org)
- It is part of the androgen and estrogen metabolic pathway. (pathbank.org)
Protein1
- Vitamin B 6 and its derivative pyridoxal 5'-phosphate (PLP) are essential to over 100 enzymes mostly involved in protein metabolism . (oregonstate.edu)
Vitamin3
- Growing evidence from experimental and clinical studies suggests that systemic inflammation underlying most chronic diseases may impair vitamin B 6 metabolism. (oregonstate.edu)
- Pharmacologic doses of vitamin B 6 are used to treat seizures in rare inborn errors of vitamin B 6 metabolism. (oregonstate.edu)
- Several medications, including anti- tuberculosis drugs, anti-parkinsonians, nonsteroidal anti- inflammatory drugs, and oral contraceptives, may interfere with vitamin B 6 metabolism. (oregonstate.edu)
Biochemical1
- Here we conduct a review of omics-based PFAS exposure studies using laboratory ecotoxicological methodologies and environmentally relevant exposure levels and show that common biochemical response pathways are identified in multiple studies. (bvsalud.org)
Nitrogen1
- The development of a pathway for nitrogen disposal in a species appears to depend chiefly on the availability of water. (medmuv.com)
Residues1
- This variant showed substitution of methionine residues due to misincorporation of O -methyl- l -homoserine, also called methoxine. (biomedcentral.com)
Homocystinuria1
- Homocysteinemia may be due to a genetic predisposition to abnormal activity in the same pathways as homocystinuria. (medscape.com)
Glucose1
- Zinc exposure resulted in a reduction in levels of intermediates in carbohydrate metabolism (i.e., glucose 6-phosphate, fructose 6-phosphate and disaccharides) and an increase in a number of TCA cycle intermediates. (bvsalud.org)
Fatty1
- This includes the fatty acid pathway, the beta oxidation pathway, which is how we move long chain fatty acids into the micochondria and if that pathway is inhibited, then we might see high levels of adipic and suberic acid and this often indicates an unmet need for magnesium or B2 or L-carnitine. (drweitz.com)
Organic1
- L-Cysteine, also known as C or e 920, belongs to the class of organic compounds known as cysteine and derivatives. (cannabisdatabase.ca)
Aspartate1
- Where does methionine belong in the aspartate family? (rhumbarlv.com)
Cofactor1
- The enzyme belongs to the γ-family of PLP-dependent enzymes due to its use of a pyridoxal-5'-phosphate (PLP) cofactor to cleave cystathionine. (wikipedia.org)
Rats1
- Rats were fed for 6 weeks the following diets, that is, control, 0.5% quercetin, 1.0% methionine, and 1.0% methionine plus 0.5% quercetin diets. (hindawi.com)
Utilization2
- What is being dealt with is sulfur metabolism and utilization. (metabolichealing.com)
- The first step in the methanol utilization (MUT) pathway is catalyzed by two alcohol oxidases (Aox1 and Aox2) that are strongly induced when P. pastoris is grown on methanol [ 4 ]. (biomedcentral.com)
Cycle2
- The methionine metabolism cycle (MMC) plays important roles in regulating both methionine and cysteine homeostasis [ 1 ], and is related with functions in terms of cell growth and development under normal conditions [ 2 , 3 ]. (biomedcentral.com)
- And there are heavy metals and toxins that can inhibit these metabolic pathways, like the Kreb's Citric Acid Cycle, and some of these toxins are measured on the NutrEval. (drweitz.com)
Disorder1
- Genetically transmitted error of metabolism of the amino acid methionine leading to a multisystemic disorder of the connective tissue, muscles, central nervous system, and cardiovascular system. (mhmedical.com)
Nutritional1
- Hyperhomocysteinemia (HHcy) is associated with genetic and nutritional abnormalities in Hcy metabolism and has been demonstrated to be an independent risk factor for cardiovascular disease and several other diseases [ 4 - 7 ]. (hindawi.com)
Toxic1
- L-Cysteine is a potentially toxic compound. (cannabisdatabase.ca)
Consumption1
- This could make L-cysteine a potential biomarker for the consumption of these foods. (cannabisdatabase.ca)
Form1
- An optically active form of cysteine having L-configuration. (cannabisdatabase.ca)