title: [Detection and properties of L-threonine-L-serine dehydratase in human liver].
abstract: It has been shown that in liver extract of men deceased by different causes, L-threonine and L-serine dehydratase activities probably, belonging to only one enzyme--L-threonine-L-serine dehydratase--are found. Both activities and their ratios depend on K+ concentration both in the buffer used for enzyme extraction and in the reaction medium. Before extraction of active and stable forms of enzyme the liver is to homogenized in a buffer containing 0.15 M KCl. Both enzymatic activities have a pH-optimum at pH 9.6--10.0. It was shown that D-isomers of threonine and serine are not dehydratated and do not inhibit dehydratation of L-isomers. Studies of dependence of L-threonine and L-serine dehydratase reaction rates on temperature showed that at any temperature ranges the energy activation values are higher for the L-threonine dehydratase reaction than for the L-serine dehydratase reaction and that the ratio reaction rates for both reactions depends on temperature.
mesh_terms: D002384:Catalysis; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D012695:L-Serine Dehydratase / Q000032:analysis*; D008099:Liver / Q000201:enzymology*; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000494:pharmacology; D011732:Pyridoxal Phosphate / Q000494:pharmacology; D013237:Stereoisomerism; D013379:Substrate Specificity; D013696:Temperature; D013913:Threonine Dehydratase / Q000032:analysis*
chemical_list: D011732:Pyridoxal Phosphate; D012695:L-Serine Dehydratase; D013913:Threonine Dehydratase; D011188:Potassium
vernacular_title: Obnaruzhenie i svoĭstva L-treonin-L-serindegidratazy pecheni cheloveka.