Stelmaszyńska T, Zgliczynski JM. N-(2-Oxoacyl)amino acids and nitriles as final products of dipeptide chlorination mediated by the myeloperoxidase/H2O2/Cl- system.
Eur J Biochem 1978;
92:301-8. [PMID:
215410 DOI:
10.1111/j.1432-1033.1978.tb12748.x]
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Abstract
The chlorination of dipeptides by the myeloperoxidase/H2O2/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 at mixture of N-monochloropeptides and N-dichloropeptides was formed owing to the dismutation of N-monochloroamine to N-dichloroamine. N-Monochloropeptides decompose, yielding NH3 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.
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