Regulation of mammalian asparagine synthetase by adenine nucleotides.

Initial velocity kinetic data indicate that ADP and AMP are inhibitors of mammalian liver asparagine synthetase. The non-product nucleotide ADP is a much more potent inhibitor than AMP, although both apparently compete for the same site. This modifier site, however, does not overlap spatially with the substrate site for ATP. Both ADP and AMP are V_max inhibitors, but ADP also raises the K_m for ATP. Adenylate energy charge, calculated at various levels of ATP and ADP show typical correlations with activity, but with AMP these correlations are weak and atypical.