title: [Regulation by nicotinic acid of malate dehydrogenase activity in tissues of Black Sea mussels].
abstract: Nicotinic acid was studied for its effect on the malate dehydrogenase activity from mussels' tissues and on its ability to link substrate and coenzyme. NADH and nicotinic acid in high concentrations are shown to produce an inhibiting effect on the reverse malate dehydrogenase reaction which is determined by the nonspecific action either of the vitamin or its metabolites. When pH of the medium is shifted toward the acid zone the affinity of the enzyme to the coenzyme decreases. This phenomenon may be one of the mechanisms of the mussel organism adaptation to anaerobiosis.
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000201:enzymology*; D003067:Coenzymes / Q000378:metabolism; D007700:Kinetics; D008291:Malate Dehydrogenase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D009525:Niacin / Q000494:pharmacology*; D013379:Substrate Specificity
chemical_list: D003067:Coenzymes; D009243:NAD; D009525:Niacin; D008291:Malate Dehydrogenase
vernacular_title: Izuchenie reguliatsii nikotinovoĭ kislotoĭ aktivnosti malatdegidrogenazy tkaneĭ chernomorskikh midiĭ.