Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1975562 | Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology | 2011 | 8 Pages |
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 Ki 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 0.2 mM Fe3+ and 0.6 mM Zn2+.
Keywords
Related Topics
Life Sciences
Biochemistry, Genetics and Molecular Biology
Biochemistry
Authors
An-Chin Lee, Kuen-Tsung Lee, Li-Ying Pan,