Abstract
When phenylacetic acid-1-14C was incubated with mycelial mats of Rhizoctonia solani, the compound was converted to 14C-labeled m-hydroxyphenylacetic acid. This specific meta-hydroxylation by the fungus was slightly inhibited by 10-3M pentachloronitrobenzene although there was no further mycelial growth of the fungus. No hydroxyphenylacetic acid was found after incubation with boiled mycelial mats. Thus, the conversion appears to be enzymatic. Twelve analogues of phenylacetic acid were used to examine substrate specificity of this hydroxylation. Benzoic and phenoxyacetic acids were hydroxylated only at the para-position. Traces of m-hydroxy derivatives were formed from phenylpropionic and trans-cinnamic acids. Many other hydroxy isomers were also detected in these cases. Some other aromatic acids were not converted into their corresponding hydroxy acids. Thus, phenylacetic acid was the only good substrate found for specific meta-hydroxylation by R. solani.
