Production of ABO blood group antigens

HO CHZOH QQQQ OH Enzyme products of the \ ABO gene can modify the H antigen. H antigen CH CH CH OH CH OH NHOCH3 B- transferase encoded by I3 O—Lipid——-> A antigen CH20H CHOH CHOH CHZOH CHZOH O OH 0— Lipid NHOCH3 NHOCH3 A-transferase adds N—acetylgalactosamine HO to the H antigen to convert it to A antigen. OH A-transferase H antigen encoded byO IA CH OH CH OH CH CH CH OH NO functionalH transferase — Lipid encoded by i NHOCH H antigen is unmodified HO ’ OH 7‘ The H antigen is produced by action of the H gene. ‘ B antigen CH OH CH OH CH CH CH OH CH CH powwow NHOCH3 HO B—transferase adds galactose to the H OH antigen, converting it to B antigen.