• superfamily
  • ATP-binding cassette transporters (ABC transporters) are members of a transport system superfamily that is one of the largest and is possibly one of the oldest families with representatives in all extant phyla from prokaryotes to humans. (wikipedia.org)
  • mitochondrial
  • Recent work has defined a new tolerance mechanism, ie, an inhibition of mitochondrial aldehyde dehydrogenase, the enzyme that accomplishes bioactivation of nitroglycerin, and has identified mitochondria as an additional source of reactive oxygen species. (ahajournals.org)
  • Formate is toxic because it inhibits mitochondrial cytochrome c oxidase, causing hypoxia at the cellular level, and metabolic acidosis, among a variety of other metabolic disturbances. (wikipedia.org)
  • soluble
  • There is a major consent that the principle mechanism of GTN-induced smooth muscle relaxation is the activation of the intracellular NO receptor enzyme, soluble guanylyl cyclase (sGC), subsequent elevation of the cyclic GMP (cGMP) levels, and activation of cGMP-dependent protein kinases, and/or cyclic nucleotide-gated ion channels. (ahajournals.org)
  • proteins
  • Reflecting the increased amino acid transport capacity of tumor cells, F-18 fluroethyltyrosine (F-18 FET) is actively taken up in tumor cells via amino acid transport system L, but is neither incorporated into proteins nor readily degraded, resulting in high intracellular concentrations of this imaging agent. (newyorkoncology.com)
  • The toxicity of sanguinarine has been shown to be dependent on the reactivity of its iminium bond with nucleophilic sites like thiol groups, present at the active sites of the enzymes and other vital proteins and thus suggesting the electrophilic nature of the alkaloid. (wikipedia.org)
  • Like the ABC exporters, it is possible that the integral membrane proteins of ABC uptake systems also evolved at least 3 times independently, based on their high resolution 3-dimensional structures. (wikipedia.org)
  • lanosterol
  • Although lanosterol 14α-demethylase is present in a wide variety of organisms, this enzyme is studied primarily in the context of fungi, where it plays an essential role in mediating membrane permeability. (wikipedia.org)
  • The enzyme-catalyzed demethylation of lanosterol is believed to occur in three steps, each of which requires one molecule of diatomic oxygen and one molecule of NADPH (or some other reducing equivalent). (wikipedia.org)
  • catalyzes
  • CYP2A6 is the only enzyme in the human body that appreciably catalyzes the 7-hydroxylation of coumarin, such that the formation of the product of this reaction, 7-hydroxycoumarin, is used as a probe for CYP2A6 activity. (wikipedia.org)
  • substrate
  • A second precaution with respect to predicting FMO enzyme substrate specificity is that factors other than size and charge must play a role, but these parameters are not well understood. (wikipedia.org)
  • An example is the high selectivity observed with human FMO3, compared to the other FMO enzymes, in the N-oxygenation of the important constitutive substrate trimethylamine (Lang et al. (wikipedia.org)
  • During the first two steps, the 14α-methyl group undergoes typical cytochrome monooxygenation in which one oxygen atom is incorporated by the substrate and the other is reduced to water, resulting in the sterol's conversion to a carboxyalcohol and then a carboxyaldehyde (Lepesheva et al. (wikipedia.org)
  • hydrocarbon
  • Condensation of methanol molecules to produce hydrocarbon chains and even aromatic systems has been demonstrated with loss of water, carbon monoxide, and/or carbon dioxide (loss of oxygen is prohibited on thermodynamic grounds). (wikipedia.org)
  • humans
  • It is the sole enzyme capable of synthesizing aldosterone in humans and plays an important role in electrolyte balance and blood pressure. (wikipedia.org)
  • protein
  • It is a protein which is only expressed in the zona glomerulosa of the adrenal cortex and is primarily regulated by the renin-angiotensin system. (wikipedia.org)
  • Most but not all uptake systems also have an extracytoplasmic receptor, a solute binding protein. (wikipedia.org)
  • molecular
  • These enzymes use both molecular oxygen and two NADPH's to dehydrate one of the hydroxyl groups on the anthraquinone and open the quinine with the molecular oxygen. (wikipedia.org)
  • NADPH
  • The systematic name of this enzyme class is (S)-N-methylcanadine,NADPH:oxygen oxidoreductase (14-hydroxylating). (wikipedia.org)
  • oxygen
  • Nevertheless, recent data indicate that GTN-induced reactive oxygen species (ROS) formation may inhibit the GTN-metabolizing enzyme. (ahajournals.org)
  • This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. (wikipedia.org)
  • activity
  • Lower activity of CYP1A2 in South Asians appears to be due to cooking these vegetables in curries using ingredients such as cumin and turmeric, ingredients known to inhibit the enzyme. (wikipedia.org)
  • These sterols localize to the plasma membrane of cells, where they play an important structural role in the regulation of membrane fluidity and permeability and also influence the activity of enzymes, ion channels, and other cell components that are embedded within (Daum et al. (wikipedia.org)
  • activities
  • Activities of antioxidant enzymes were analysed in freshwater prawn Macrobrachium malcolmsonii during embryonic and larval development. (wikipedia.org)
  • therefore
  • This type of molecules already have reactive and polar groups comprised within their structure therefore phases I enzymes are less active than phase II (conjugation) enzymes. (wikipedia.org)
  • cell
  • It functions by inhibiting DNA gyrase, a type II topoisomerase, and topoisomerase IV, enzymes necessary to separate bacterial DNA, thereby inhibiting cell division. (wikipedia.org)
  • process
  • The enzyme starts the process of inactivating and degrading leukotriene B4, a potent mediator of inflammation. (abnova.com)
  • level
  • An elevated level of antioxidant enzymes was encountered in the larval stage of M. malcolmsonii when compared to its preceding embryonic stages. (wikipedia.org)
  • In order to detoxify these oxyradicals an enhanced level of antioxidant enzymes were found in malcolmsonii larvae. (wikipedia.org)
  • several
  • Several sampling and analytical methods including thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), mass spectrometry, and enzyme-linked immunosorbent assay (ELISA), among others, have been used to test for aflatoxin B1 contamination in foods. (wikipedia.org)
  • Most of the enzymes have not been characterized and there may be several more intermediates that are still unknown. (wikipedia.org)
  • close
  • Upon forming the aldehyde in the ring opening step, it is oxidized to form the carboxylic acid and subsequently a decarboxylation event occurs to close the ring, forming the six-member ether ring system seen in demethylsterigmatocystin. (wikipedia.org)