FIELD: biochemical methods. SUBSTANCE: stabilization of enzyme is achieved by adding to its aqueous solution or suspension N-protected amino acid. When N-benzyloxycarbonylated amino acid is added to metalloprotease, the latter remains stable even in absence of excess of Ca ions. Enzyme can therefore be stored for a long time and also storage and transportation of liquid enzyme form are simplified. Regeneration of metalloprotease is improved in presence of N-protected amino acid when enzyme is used in reaction of binding between N-protected amino acid and amino acid ester. Most marked effect is observed in production of aspartame by reaction of benzyloxycarbonylaspartic acid with phenylalanine methyl ester. EFFECT: inhibited deactivation of metalloprotease and improved its stability. 8 cl, 6 tbl, 8 ex
