Open AccessN ‐(2‐Oxoacyl)amino Acids and Nitriles as Final Products of Dipeptide Chlorination Mediated by the Myeloperoxidase/H 2 O 2 /Cl − System
Author(s) -
STELMASZYŃSKA Teresa,
ZGLICZYNSKI Jan M.
Publication year - 1978
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1978.tb12748.x
Subject(s) - chemistry , amino acid , dipeptide , hydrogen cyanide , amide , peptide , cyanide , chloride , organic chemistry , oxidizing agent , peptide bond , medicinal chemistry , stereochemistry , biochemistry
The chlorination of dipeptides by the myeloperoxidase/H 2 O 2 /Cl − system takes place at the N‐terminal amino group, whereas no chlorination of the amide nitrogen of the peptide bond can be observed. The N ‐terminal amino group is chlorinated to N ‐monochloroamine or/and N ‐dichloroamine. N ‐Monochloropeptides were the main products at higher pH values, at lower pH a mixture of N ‐monochloropeptides and N ‐dichloropeptides was formed owing to the dismutation of N ‐monochloroamine to N ‐dichloroamine. N ‐Monochloropeptides decompose, yielding NH 3 and the corresponding N ‐(2‐oxoacyl)amino acids. N ‐Dichlorodipeptides decompose faster but to nitriles and the free C‐terminal amino acids. N ‐Dichloroglycyl‐amino acid decomposes through a relatively stable intermediate (cyano‐formylamino acid) to hydrogen cyanide, cyanogen chloride and the free C‐terminal amino acid. Insulin chlorination also yields N‐terminal glycyl and phenylalanyl N ‐monochloro derivatives, which deaminate to glyoxylyl and phenylpyruvyl residues.