Interaction of trichloromethyl radicals with phenylalanine.

Chemically or enzymatically generated trichloromethyl free radicals interact with liposoluble derivatives of phenylalanine. In vitro, in a chemical system to produce .CCl3 (benzoyl peroxide catalysis), this radical attacked N-acetyl-d,l-phenylalanine methyl ester (PheMeAc) to give a monochlorinated derivative (I) and an unsaturated imine type derivative of PheMeAc (II). Using a liver microsomal system to produce .CCl3 (microsomes + NADPH + CCl4 under nitrogen), the attack of PheMeAc did not result in I or II formation, but in production of benzene. The phenylalanine content in liver microsomal proteins from rats treated with CCl4 6 h before, was not significantly decreased. The results suggest that phenylalanine is a potential target of .CCl3.