Some Properties of Glycine Aminotransferase Purified from Rhodopseudomonas palustris No. 7 Concerning Extracellular Porphyrin Production(Microbiology & Fermentation Technology)

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Glycine aminotransferase (EC 2. 6. 1. 4 ; GlyAT) was presumed to be an enzyme concerning the supply of glycine for the extracellular porphyrin production by Rhodopseudomonas palustris No. 7. GlyAT was purified from strain No. 7 as an electrophoretically homogeneous protein. The enzyme was a monomer protein with the molecular weight of about 42,000. From the absorption spectrum of the enzyme (350 nm, 410 nm), it was indicated that the enzyme had pyridoxal phosphate as a prosthetic group. The enzyme showed high substrate specificity for glutamate as an amino group donor. Apparent K_ms for glutamate and glyoxylate were 6.20 mM and 3.75 mM, respectively. The V_<max> and K_<cat> for glutamate were 66.8μmol/min/mg protein and 46.8 s^<-1>, respectively. The V_<max> and K_<cat> for glyoxylate were 68.8μmol/min/mg protein and 48.2s^<-1>. The optimum temperature and pH were 40〜45℃ and 7.0〜7.5, respectively. The enzyme activity lowered to about 50% in the presence of 15 mM ammonium chloride.
社団法人日本農芸化学会の論文
2003-04-23