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Abstract
The kinetics of phenol methylation by chloromethane (CH3Cl) in intact mycelia of the fungus Phellinus pomaceus were examined. Anisole was produced linearly with respect to time at a rate of 6·3 nmol g−1 h−1 over 16 h when washed mycelia were incubated with phenol and C2H3Cl. Incorporation of C2H3- label into anisole attained a plateau value of 27% within 2 h. The rate of anisole production under N2 was only 36% of that in air, and the proportion of C2H3- label incorporated from exogenous C2H3- increased from 30 to 45% under these conditions. The rate of methylation attained a maximum in 10 mm-phenol, but the level of activity was only about 10% of that of the fungal carboxyl-methylating system. The presence of exogenous C2H3Cl clearly stimulated anisole formation, demonstrating that the rate of CH3Cl biosynthesis limited methylation to some extent. In contrast to the carboxyl-methylating system, no significant inhibition of methylation was observed at methyl acceptor concentrations up to 17·5 mm, and no sharp fall in the rate of gaseous C2H3Cl release or rapid increase in C2H3-incorporation were observed at supraoptimal concentrations of acceptor, indicating that endogenous CH3Cl biosynthesis was not inhibited under these conditions. Investigations of the rate of C2H3- incorporation into anisole from exogenous C2H3Cl showed a linear relationship between the logarithm of % C2H3- incorporation and the logarithm of C2H3Cl concentration, suggesting that, as postulated for the carboxyl-methylating system, the CH3Cl-synthesizing and CH3Cl-utilizing enzyme systems were situated on either side of a membrane within the cell.
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