Description
The enzyme catalyses the successive reduction of the geranylgeraniol esterifying group to phytol, reducing three out of four double bonds, and transforming geranylgeranyl bacteriochlorophyllide a via dihydrogeranylgeranyl bacteriochlorophyllide a and tetrahydrogeranylgeranyl bacteriochlorophyllide a to bacteriochlorophyll a. The enzyme can also accept the pheophytin derivative geranylgeranyl bacteriopheophytin, converting it to bacteriopheophytin a