Zur Kenntnis des intermediären Stoffwechsels des Histidins. II. Mitteilung.

Abstract

As yet histidinase has been found only in extracts of the liver. It is not the same as arginase. Histidine is broken down to 2 molecules of ammonia, one of glutamic acid and probably one of formic acid. The reaction proceeds by way of intermediates as yet unknown, possibly through pyrollidon carboxylic acid as a precursor of glutamic acid. The enzyme has decided specificity, attacking only the naturally occurring optical isomer, but not imidazole, imidazole-lactic acid, imidazole-ethylamine, methylhisti-dine, and probably not carnosine and the methyl ester of histidine. Since no reaction occurs on the optically active carbon atom, it seems evident that the naturally occurring 1-histidine and d-glutamic acid belong to the same stereochemical group.