Phosphorolysis of citrulline by mammalian liver: the effect of a bacterial activator

Publisher Website
Google Scholar
Abstract
A heat-labile bacterial "factor" (other than ornithine decarboxylase) capable of stimulating the phosphorolysis of citrulline by mammalian liver was purified 15-fold by ammonium sulfate fractionation. The purified preparation and washed suspensions of several strains of Escherichia coli were tested for "factor" activity and carbamyl phosphatase activity, because acceleration of the hydrolysis of carbamyl phosphate might account for the "factor" activity. Carbamylphosphatase activity was found in all "factor" preparations, but there was no parallelism with "factor" activity. The latter was absent from rat spleen, kidney and liver, although these tissues rapidly hydrolyzed carbamyl phosphate, and E. coll N.C.I.B. 8571 was the only one of 6 strains which had appreciable "factor" activity. Adenosine 5[image]-phosphate, L-aspartate, L-asparagine, fumarate and glycerol each stimulated "factor" activity but had no effect on the enzymic hydrolysis of carbamyl phosphate. This stimulation generally increased with time. Some characteristics of the bacterial hydrolysis of carbamyl phosphate are described. The results indicate that the bacterial "factor" is not a carbamylphosphatase.