Confirmation of the site of nitrosation in tryptophan derivatives by α-chymotrypsin

Abstract

N-Aroyl derivatives of aromatic hydrophobic L-amino-acid esters (1)–(7) are hydrolysed by α-chymotrypsin to the corresponding L-amino-acids (8)–(14). When the amidic nitrogen atom is incorporated into a heterocyclic ring, e.g. in the benzotriazinones (15a and b), substrate properties are lost. The N-nitroso-derivatives of N-acetyl-L-tryptophan methyl and ethyl esters are smoothly hydrolysed by α-chymotrypsin; their nitroso-groups are therefore attached to the indolic rather than the amidic nitrogen atom.