a bacteriochlorophyllide d + S-adenosyl-L-methionine => a bacteriochlorophyllide c + S-adenosyl-L-homocysteine + H(+)
a bacteriochlorophyllide d + s-adenosyl-l-methionine => a bacteriochlorophyllide c + s-adenosyl-l-homocysteine + h(+)