Proteolytic processing of N-glycosylation mutants . A Vero cells expressing either wild-type GP-C or GP-1 N-glycosylation mutants T81A, S91A, T101A, S111A, S121A, S169A and T226A. B Vero cells expressing either wild-type GP-C or GP-2 N-glycosylation mutants S367A, S375A, S392A and S397A. The expressed proteins were separated by SDS-PAGE on 12% acrylamide gels and immunoblotted. Non-cleaved GP-C and its cleaved form GP-2 are detected by immunostaining using the antiserum rb-α-GP-2.