Solubilization and purification of galactosyltransferase from golgi membranes of rat ventral prostate.

UDP-galactose ovomucoid galactosyltransferase, a membrane-bound enzyme involved in the biosynthetic pathways for formation of the nonreducing terminal oligosaccharide sequences on glycoproteins, has been solubilized and purified from rat ventral prostate Golgi membranes.Solubilization was effected by treatment of the particulate fraction with Triton X-100 (0.5% v/v) and MnCl2 (25 mM). The solubilized enzyme was purified by affinity chromatography on hen ovomucoid-sepharose column.The purified galactosyltransferase showed three protein bands of approx. 74,000, 60,000, and 54,000 daltons on sodium dodecyl sulfate gel electrophoresis. On gel filtration, enzyme activity eluted at approx. 70,000 daltons with a broad shoulder between 60,000 and 50,000 daltons.Isoelectric focusing of the purified enzyme resolved at least five active bands with pHi of 9, 7.4, 6.75, 6.1, and 4.8.