FIGURE 2.

Chimeric glycoprotein substrates used for characterization of GalNAc transfer in vitro and in vivo. Plasmids pCMV-GlucCG-CTP-CA(1–19)Myc-His and pCMV-GlucCG-CTP-CA(1–2)Myc-His encoding chimeric proteins consisting of GLuc, the CTP sequence, the CA1–19 sequence, or the CA1–2 sequence, respectively, and the epitope tag Myc-His were prepared. The Ser residues in the CTP that have been shown to be modified with O-linked GalNAc when expressed in CHO cells are indicated by asterisks. The sequence of the 19-amino acid carboxyl terminal peptide from CA6 is shown, and the residues deleted from the sequence to generate CA(1–2) are blocked out with a black line.