The Degradation of Histidine by Aerobacter Aerogenes* by Boris Magasanik

In the course of the studies presented in the preceding paper it was observed that Aerobacter aerogenes could grow on histidine as the sole source of carbon and nitrogen (1). The nature of the microbial enzymes responsible for the complete degradation of histidine was not known and appeared therefore to be an appropriate subject for investigation. After initiation of these studies, the results of the investigations of Tabor and his collaborators on the degradation of histidine by Pseudomonas Jluorescens were published (2, 3). It became apparent that the histidine metabolism of A. aerogenes and of P. jtuorescens followed the same general pattern (also observed in mammalian liver (4)), yet with significant differences. The present paper describes the dissimilation of histidine in A. aerogenes and compares the pathways of histidine degradation of the two microorganisms.