Figure 7.

Enzymatic digests of endogenous granule proteoglycan. Nontransfected AtT-20 cells and AtT-20 cells expressing basic PRP (+bPRP) were labeled and chased as described in Figure 6. Media from 8-Br-cAMP-stimulated cells were digested with chondroitinase AC and heparinase III as described in MATERIALS AND METHODS. Labeled polypeptides were precipitated with TCA and analyzed by SDS-PAGE and fluorography. Cont, control; Ch, chondroitinase AC; H, heparinase III. The bracket indicates the position of the endogenous granule proteoglycan.