학술논문
D-Amino acids of the amino acid pool and occurrence of racemase and D-amino acid oxidase activities in Escherichia coli B.
Document Type
Academic Journal
Author
Source
Publisher: Springer Country of Publication: United States NLM ID: 0376757 Publication Model: Print Cited Medium: Print ISSN: 0015-5632 (Print) Linking ISSN: 00155632 NLM ISO Abbreviation: Folia Microbiol (Praha) Subsets: MEDLINE
Subject
Language
English
ISSN
0015-5632
Abstract
Less than 20% of the amino acid content of the amino acid pool of Escherichia coli B exists in the D-form. Alanine, glutamic acid, and valine were shown by gas- chromatography to be partially in the D-form. Only D-alanine was formed by racemization in the crude extract of this organism. Alanine racemase was easily released from the membranes or vesicles but D-alanine oxidase activity remained firmly bound to the membrane. Most protein amino acids stimulated proline uptake into the vesicles, and the oxidative deamination activities were verified by the proline uptake stimulating amino acids. It is concluded that the obligatory pathway of L-amino acid--D-amino acid--oxo acid which exists in the oxidation of L-alanine does not exist with other L-amino acids. It is likely that other D-amino acids in the pool are formed in the presence of D-amino acid oxidase or D-amino acid aminotransferase.