FIGURE 4.

Protein glycosylation studies of xpt1Δ mutant. Total membranes prepared from the indicated strains were assayed with UDP-[¹⁴C]Xyl in the presence (+) or absence (−) of MnCl₂ as indicated; some samples were subsequently mock-treated (m) or treated with protease (+) as indicated. Panel A shows manganese stimulation of radiolabel incorporation. Panel B shows protease degradation of assay products. Panel C shows Xpt1p dependence of radiolabel incorporation. Autoradiographs of dried SDS-PAGE gels are shown. Molecular weight standards (in kDa) are indicated at the right.