Phenol Conjugation with Peptides and Final Transformations of Conjugates in English Ryegrass Seedlings

Abstract

[ 1-14C] Phenol transformation in English ryegrass (Lolium perenne L.) sterile seedlings was studied. The compound studied was assimilated by a plant through leaves as vapor. Phenol was bound with ryegrass low-molecular-weight peptides producing phenol-peptide conjugates. Conjugation with endogenous peptides is one of the main pathways of phenol detoxication in ryegrass. Nearly three fifths of phenol assimilated is conjugated with low-molecular-weight peptides. After removal of the plant from the labeled phenol-containing atmosphere, the content of conjugation products gradually decreased, followed by excretion of labeled carbon dioxide. This fact indicates that the conjugates are destructed and the carbon atoms of their radioactive component are oxidized to carbon dioxide. Almost one third of assimilated phenol is transformed via the oxidation pathway, but a small part of it is irreversibly bound with biopolymer molecules.