title: Purification and kinetic characteristics of strombine dehydrogenase from the foot muscle of the hard clam (Meretrix lusoria).
abstract: Strombine dehydrogenase (SDH, EC 1.5.1.22) from the foot of the hard clam Meretrix lusoria was purified over 470-fold to apparent homogeneity. It has a monomeric structure with a relative molecular mass of 46,000. Two isoenzymes were identified with isoelectric points of 6.83 and 6.88. SDH is heat labile, and has pH and temperature optima of 7.4-7.6 and 45-46°C, respectively. l-Alanine, glycine, and pyruvate are the preferred substrates. l-Serine is the third preferred amino acid. Iminodiacetate with the lowest K(i) of SDH at both pH 6.5 and 7.5 was the strongest inhibitor among succinate, acetate, iminodiacetate, oxaloacetate, and l-/d-lactate. The inhibitory activities of succinate at pH 6.5, and iminodiacetate and oxaloacetate at pH 7.5 on the SDH were higher. These inhibitors are either competitive or mixed-competitive inhibitors. Half of the enzymatic activity of SDH was inhibited by 0.2mM Fe(3+) and 0.6mM Zn(2+).
authors.affiliation: Department of Aquatic Biosciences, College of Life Science, National Chiayi University, Chiayi 600, Taiwan. aclee@mail.ncyu.edu.tw
authors.forename: An-Chin
authors.initials: AC
authors.lastname: Lee
authors.forename: Kuen-Tsung
authors.initials: KT
authors.lastname: Lee
authors.forename: Li-Ying
authors.initials: LY
authors.lastname: Pan
mesh_terms: D000085:Acetates / Q000494:pharmacology; D000818:Animals; D049872:Bivalvia / Q000033:anatomy & histology* / Q000201:enzymology*; D004789:Enzyme Activation / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D019344:Lactic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D009132:Muscles / Q000201:enzymology*; D010071:Oxaloacetates / Q000494:pharmacology; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000037:antagonists & inhibitors / Q000302:isolation & purification* / Q000378:metabolism*; D013329:Structure-Activity Relationship; D019802:Succinic Acid / Q000494:pharmacology; D013696:Temperature
chemical_list: D000085:Acetates; D010071:Oxaloacetates; D019344:Lactic Acid; D019802:Succinic Acid; D000587:Oxidoreductases Acting on CH-NH Group Donors; C036085:strombine dehydrogenase