The influence of nutrition on the serine and threonine deaminases of microorganisms.

Studies concerning the identity of the serine and threonine deaminases have been carried out in several laboratories. Wood and Gunsalus (1949) employing a partially purified system extracted from Escherichia coli suggested that both serine and threonine are deaminated by the same enzyme. Similarly, studies with Neurospora indicate that these amino acids are deaminated by one enzyme (Yanofsky, 1952; Yanofsky and Reissig, 1953). In contrast, Dawes (1952) reported data which were interpreted to suggest that the serine deaminase and threonine deaminase are separate and distinct enzymes, and Lichstein (1951) suggested the possibility that two enzymes requiring the same cofactors are concerned in the deamination of these two amino acids. The results of the present study reveal that although closely related the deaminases of serine and threonine appear to be separate and distinct enzyme systems.