The presence of two serine racemases in Streptomyces garyphalus,a d-cycloserine producer |
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Authors: | Marie-Louise Svensson Sten Gatenbeck |
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Affiliation: | (1) Department of Biochemistry and Biotechnology, Koyal Institute of Technology, S-100 44 Stockholm, Sweden |
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Abstract: | Two serine racemases (I and II) were isolated from Streptomyces garyphalus. Serine racemase I (molecular weight 93,000) was purified to a single band in an analytical electrofocusing system. Serine racemase II (molecular weight 73,000) was partially purified. Both enzymes used pyridoxal-5-phosphate as cofactor. Besides serine the enzymes utilized alanine as substrate but no other amino acid tested. The K
m values of l-alanine and l-serine for enzyme I were 111 mM and 35 mM respectively. Enzyme I was not inhibited by d-cycloserine but by hydroxylamine. Both substances inhibited enzyme II. The serine racemases may be involved in the biosynthesis of d-cycloserine in S. garyphalus. |
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Keywords: | Serine racemase Alanine racemase d-cycloserine" target="_blank">d-cycloserine Streptomyces garyphalus |
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