Formimino-L-glutamic acid

Dilute enzyme solutions of the above microorganisms convert urocanic acid to iV-formimino-L-glutamic acid as do also liver enzyme preparations. 

When a crude liver extract is added to the purified urocanase, decomposition of urocanic acid proceeds to W-formimino-L-glutamic acid. The enzyme carrying out this stage of the reaction has been named imidazolonepropionic acid hydrolase. In view of the fact that im-idazolonepropionic acid has not been isolated and study of the hydrolysis reaction can only be performed in incubation mixtures in which urocanic acid is reacted with purified urocanase very little is known about the properties of the hydrolase enzyme. This enzyme has been purified about tenfold by ammonium sulfate fractionation in our laboratory (266). The enzyme activity is shown by an acceleration in the rate of the decomposition of the 264 my absorption. The product formed was shown to be formimino glutamic acid by testing with purified formiminotransferase which is specific for this compound. 

B36. Broquist, H. P., and Luhby, A. L., Detection and isolation of formimino-glutamic acid from urine in folic acid deficiency in humans. Proc. Soc. Exptl. Biol. Med. 100, 349-354 (1959). 

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