Detoxication of phenol in annual plant seedlings

Transformation of phenol ((C6H5OH)-C-14) penetrating through the roots of m ung bean (Phaseolus aureus) and wheat (Triticum vulgare) sterile seedlings has been studied. Phenol was coupled to low-molecular- weight peptides, pro ducing phenol-peptide conjugates. Hydrolytic cleavage of the conjugates lib erated initial labeled phenol and some unlabeled amino acids. Phenol-glutat hione and phenol-homoglutathione were not found among the peptide conjugate s. It is suggested that the conjugation is carried out via the hydroxyl gro up of phenol and functional groups of peptides. Conjugation with low-molecu lar-weight peptides is considered to be the main pathway for phenol detoxic ation, since about 60% of phenol absorbed by plants conjugates with peptide s. In the plants treated with phenol, the amount of low-molecular-weight pe ptides is increased. The increase in peptide synthesis in plants seems to b e induced by the penetration of toxic phenol molecules into the cell. The s mall amount of phenol molecules assimilated through roots is transformed vi a aromatic ring cleavage and bibasic carbonic acid formation. (C) 1999 Acad emic Press.