Abstract
N4-Ethyl-L-[u-14C]asparagine and L-[U-14C]aspartate give identical metabolites, mainly intermediates of the tricarboxylic acid cycle and related amino acids, in whole cells of Pseudomonas stutzeri. The labelled asparagine derivative is converted into [14C]-aspartate by cell-free extracts, and this reaction, which has an optimum pH of 8.8 +/- 0.2, is neither inhibited by unlabelled asparagine nor enhanced by unlabelled 2-oxoglutarate. No labelled keto acid corresponding to N4-ethylasparagine was detected in either whole cells or cell-free extracts. Thus N4-ethyl-L-asparagine, like asparagine, must be broken down by hydrolysis, at least in this bacterium.