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The Induction and Repression and Other Studies of Alanine Racemase in Bacillus Subtilis
Abstract
D-alanine was the first D-amino acid to be shown to be an essential metabolite for bacteria (1-3), although this require- ment could be met with pyridoxal. Although it had been suggested that D-alanine might be a precursor of pyridoxal, it was later shown by Snell and his co-workers (4,5) that L-alanine could be racomized to DL-alanine with pyridoxal serving as the "coracemase". From studies of the nonenzymatic racemization of amino acids by pyridoxal and heavy metal ions, Snell postulated that a metal ion stabilized Schiff base is formed by interaction of the a-amino group and pyridoxal and that upon a simple rearrangement of the intermediate by the prototropic shift the asymmetry of the a-carbon is destroyed (4,5). Fyruvate was shown not to be an intermediate.The enzymatic racemization of alanine was demonstrated by Wood and Gunsalus (6) in whole cells and extracts of Streptococcus faecalis R. An enzymatic requirement for pyridoxal phosphate was shown and the possibility of formatiion of D-alanine by trans- amination was eliminated by the failure to demonstrate the formation of D-alanine from pyruvate and a variety of known amino group donors. Thus the earlier suggestion of Holden and Snell (2) that pyridoxal phosphate acted as the cofactor for racemization as well as for transamination and other reactions was confirmed in cell free preparations. Marr and Wilson (7) were able to show in extracts of Brucella abortus that 15- into alanine during racemization. -ammonia was not incorporated
Subject Area
Biochemistry
Recommended Citation
THORNTON, MANLY PHILIP, "The Induction and Repression and Other Studies of Alanine Racemase in Bacillus Subtilis" (1967). ETD collection for University of Nebraska-Lincoln. AAI6710683.
https://digitalcommons.unl.edu/dissertations/AAI6710683