Enzymatically catalysed decarboxylation of β-carboxyaspartic acid (Asa)

Abstract

. Can. J. Chem. 68, 886 (1990). A better synthetic route to P-carboxyaspartic acid (Asa) was achieved through condensation of sodium dibenzyl malonate and benzyl2-bromoacetate as an alternative to two steps in the method of Koch et al. Catalytic hydrogenation at 5 atm pressure in a shaken stainless steel vessel removed protecting carbobenzyloxy groups. Asa was purified on a cation exchange column. An extract of E. coli was found to catalyse the decarboxylation of Asa in a doubly coupled assay designed to be specific for produced aspartic acid. Evidence for enzymatic decarboxylation includes complete loss of activity on boiling and progressive loss of activity on repeated freeze-thawing of the extract.Key words: decarboxylation, P-carboxyaspartic acid, Asa decarboxylase.