reaction of 3 '' '' -o-demethylavermectin b2a and s-adenosylmethionine with either cell extracts or purified b2omt resulted in the methylation of the oxygen at c5 of the macrolide moiety and yielded only 3 '' -o-demethylavermectin a2a as the product .
C0025831
b2om
C0025723
methylatio