Figure 4.

Silver-stained SDS/PAGE gel showing the role of O-glycosylation on IIM. Lanes: 1, PMs were pretreated by boiling in 2% SDS to inactivate the endogenous proteases, followed by extensive washing to remove inactivated proteins and residual SDS; the treated PMs were incubated with buffer only; 2, same as lane 1, except 15 milliunits/ml of O-glycosidase was included in the incubation buffer; 3, nonpretreated PMs incubated with 3 milliunits/ml of O-glycosidase; 4, same as lane 3, except protease inhibitors were included in the incubation buffer; 5, same as lane 3, except no O-glycosidase was present in the incubation buffer. The arrow indicates IIM.