Malonate 에서 배양한 Acinetobacter calcoaceticus Malate Synthase 의 정제 및 그 성질 = Purification and Characterization of Malate Synthase from Acinetobacter calcoaceticus Grown on malonate

다국어 초록 (Multilingual Abstract)

Malate synthase (EC 4.1.3.2) was induced in Acinetobacter calcoaceticus grown on malonate as a sole carbon source. The enzyme was purified by the combined methods of DEAE-Sephacel anion exchange chromatography, oxalate Sepharose 4B affinity chromatography and hydroxyapatite chromatography in an electrophoretically homogeneous form. The molecular size of the enzyme was estimated to be 75,000 dalton consisted of a single polypeptide. Optimum pH for the enzyme was about 8.0. The rate of acetyl group incorporation on variable concentraions of the substrate into malate was well fitted to a typical Michaelis-Menten kinetics. From the Lineweaver-Burk plot, K_m and V_(max) for acetyl-CoA were 1.5 × 10^(-5) M and 1 μmol/min/㎎ respectively and those for glyoxylate were 3.5 × 10^(-5) M and 0.8 μmol/min/㎎ respectively. The activity of this enzyme was inhibited by oxalate with K_i, 4 × 10^(-5) M and by glycolate with K_i, 1.4 × 10^(-4) M competitively. Pyruvate, succinate, malonate and tartrate also inhibited the enzyme activity. Antibody prepared against malate synthase from Pseudomonas fluorescens did not cross-react with the enzyme from Acinetobacter, suggesting that the enzyme isolated from two different bacteria are immunologocally different.