R11508 S-adenosyl-L-methionine:8,12-diethyl-3-vinylbacteriochlorophyllide-d C-8(2)-methyltransferase; 8,12-Diethyl-3-vinylbacteriochlorophyllide d + S-Adenosyl-L-methionine <=> 12-Ethyl-8-propyl-3-vinylbacteriochlorophyllide d + S-Adenosyl-L-homocysteine