title: Free and membrane-bound lactate dehydrogenase from white driving muscles of skate.
abstract: Purified cytoplasmic and membrane-bound lactate dehydrogenases (LDH) from white muscle of skate were characterized, Km for pyruvate and NADH for purified LDH were 150 +/- 16 and 29 +/- 7 microM, and for membrane-bound LDH were 185 +/- 22 and 7.5 +/- 1.5 microM, respectively. The membrane-bound enzyme was not inhibited by high pyruvate concentration (up to 20 mM) in contrast to purified LDH. Part of membrane-bound LDH was released by incubation in solutions with a high level of KCl (up to 1 M) or at alkaline pH. The inactivation rate during trypsin digestion for solubilized LDH was 2-3-fold higher than that for the membrane-bound enzyme.
authors.affiliation: Karadag Branch of Institute of Southern Seas Biology, Sudak region, Crimea, U.S.S.R.
authors.forename: V I
authors.initials: VI
authors.lastname: Loushchak
mesh_terms: D000818:Animals; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D008566:Membranes / Q000201:enzymology; D009132:Muscles / Q000201:enzymology*; D009243:NAD; D011773:Pyruvates; D019289:Pyruvic Acid; D012860:Skates, Fish / Q000378:metabolism*; D012995:Solubility; D013379:Substrate Specificity
chemical_list: D011773:Pyruvates; D009243:NAD; D019289:Pyruvic Acid; D007770:L-Lactate Dehydrogenase