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.