Heme O synthase Protoheme IX farnesyltransferase Heme B farnesyltransferase 318 Converts heme B (protoheme IX) to heme O by substitution of the vinyl group on carbon 2 of heme B porphyrin ring with a hydroxyethyl farnesyl side group (By similarity). COXX_ANAVT ctaB Ava_0526 MIETNVSRRHHESFLQVIQSYYQLTKPRIIPLLLITTAGSMWIAAQGQVDPVLLLVTMAGGTLAAASAQTINCIYDRDIDYDMERTRHRPMPSGKVQVRDALIFAIALAVLSFTLLTVFANLLAASLALSGIIFYVLIYTHWLKRHSTQNIVIGGAAGAIPALVGWAAVTGTLSWSAWLIFAIVFLWTPPHFWALALMIRDDYAKVGIPMLPVVEGNAATVKQIWYYTLITVVATLLLVYPLHSSGIVYAAIAISLGAVFIRKSWRLLHNPEDRPTARELFLYSISYMMLLCLGMVIDSLPLTHHLINAVINQLHLIS