cofactor chlorophyll b [methyl (3S,4S,21R)-9-ethenyl-14-ethyl-13-formyl-4,8,18-trimethyl-20-oxo-3-(3-oxo-3-{[(2E,7R,11R)-3,7,11,15-tetramethylhexadec-2-en-1-yl]oxy}propyl)phorbine-21-carboxylatato(2-)-kappa(4)N(23),N(24),N(25),N(26)]magnesium [methyl (3S,4S,21R)-9-ethenyl-14-ethyl-13-formyl-4,8,18-trimethyl-20-oxo-3-(3-oxo-3-{[(2E,7R,11R)-3,7,11,15-tetramethylhexadec-2-en-1-yl]oxy}propyl)phorbine-21-carboxylatato(2-)-kappa(4)N(23),N(24),N(25),N(26)]magnesium (SP-4-2)-((2E,7R,11R)-3,7,11,15-tetramethyl-2-hexadecenyl (3S,4S,21R)-9-ethenyl-14-ethyl-13-formyl-21-(methoxycarbonyl)-4,8,18-trimethyl-20-oxo-3-phorbinepropanoato(2-)-kappaN(23),kappaN(24),kappaN(25),kappaN(26))-magnesium CHLOROPHYLL B chlorophyll b Chlorophyll b chlorophyll chlorophyllide b chlorophyll b(1-)