Fig. 2.
Photoaffinity Labeling of the hVPAC1 Receptor with the [125I-Bpa28]VIP Probe
A, Receptors expressed in CHO cells were photoaffinity-labeled with [125I-Bpa-F28]VIP in the absence (lane 1) or presence (lane 2) of an excess of cold VIP (1 μm). B, After photoaffinity labeling cell homogenates were subjected to treatment with CNBr, peptide N-glycosidase F (PNGase F), or endopeptidase Glu-C as shown in lanes 1–3, respectively. The labeled proteins were resolved on NuPAGE 4–12% Bis-Tris Gel followed by autoradiography. See Materials and Methods for details. MW, Molecular weight.