Enzymatic conversion of formylaspartic acid to aspartic acid.

In previous investigations imidazoleacetic acid was shown to be quantitatively converted to formylaspartic acid by a partially purified enzyme preparation obtained from Pseudomonas sp. that requires DPNH’ and oxygen (2, 3). An intermediate in this process was isolated from the incubation mixture with highly purified enzyme preparations and was characterized as N-formimino-L-aspartic acid (4). Enzymatic hydrolysis of Nformiminoaspartic acid to yield formylaspartic acid and ammonia was catalyzed by a specific enzyme, FIA hydrolase. In all of these previous studies with crude extracts and purified enzyme preparations, FA was accumulated as an end product in a stoichiometric quantity, and formation of free aspartic acid was not detectable even after prolonged incubation. The purpose of this paper is to present evidence for the further degradation of FA to aspartic acid and formic acid by a specific enzyme, formylaspartic formylase, which is active only in the presence of Fe++ or Co++.