Table 1.

C-Mannosyltransferase activity in membranes from CHO cells

Source of membrane	cpm incorporated into peptide
	Dol-P-[3H]Man	GDP-[3H]Man − Dol-P	GDP-[3H]Man + Dol-P
CHO wild type	19480	664	12400
CHO Lec15	22031	46	15

The C-mannosyltransferase activity in membranes (75.5 μg of total protein) from wild-type and CHO Lec15 cells was determined using the standard peptide as the acceptor (see Figure 3) and Dol-P-[2-³H]Man as the donor. Alternatively, GDP-[2-³H]Man was tested as a donor in the absence or presence of Dol-P (0.4 mM). The amount of radioactivity incorporated into the peptide was corrected for background. The data are the average of two independent experiments.