抄録
Histochemical analyses of β−1, 4−galactosyl−transferase(β−1, 4−GalT) I−knockout mouse liver using anti−bovine β−1, 4−GalT I antibody and Ricinus communis agglutinin(RCA)−I which interacts with oligosaccharides terminated with β−1, 4−linked galactose revealed that weak fluorescence derived from the lectin is present in the mutant mouse in contrast to the disappearance of the immunofluorescence. Lectin blot analysis of membrane glycoproteins showed that many protein bands react with RCA−I although their reactivities are weak in the mutant mouse liver. Upon pretreatment of blots with β−1, 4−galactosidase or N−glycanase, no lectin binding was observed, indicating that a part of N−linked oligosaccharides of β−1, 4−GalT I-knockout mouse liver is galactosylated by yet unidentified β−1, 4−GalT. Gel filtration column chromatography of solubilized mouse liver transferases revealed that β−1, 4−GalT activities in wild-type mouse are detected in fractions 42 and 50 while those in the mutant mouse are detected only in fraction 42. The results indicate that mouse liver contains a high molecular weight β−1, 4−GalT(110K) in addition to a previously known β−1, 4−GalT(46K).
