β-aspartylpeptides as substrates of L-asparaginases from Escherichia coli and Erwinia chrysanthemi

L-Asparaginase is known to catalyze the hydrolysis Of L-asparagine to L-aspartic and ammonia, but little is known about its action on peptides. When we incubated L-asparaginases purified either from Escherichia coli or Erwinia chrysanthemi - commonly used as chemotherapeutic agents because of their antitumour activity - with eight small beta-aspartylpeptides such as beta-aspartylserineamide, beta-aspartylanineamide, beta-aspartylglycineamide and beta-aspartylglycine, we found that both L-asparaginases could catalyze the hydrolysis of five of them yielding L-aspartic acid and amino acids or peptides. Our data show that L-asparaginases can hydrolyze -aspartylpeptides and suggest that L-asparaginase therapy may affect the metabolism of P-aspartylpeptides present in human body. (C) 2002 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.