Purification and stability characterization of a cell regulatory sialoglgycopeptide inhibitor

Abstract

Previous attempts to physically separate the cell cycle inhibitory and protease activities in preparations of a purified cell regulatory sialoglycopeptide (CeReS) inhibitor were largely unsuccessful. Gradient elution of the inhibitor preparation from a DEAE HPLC column separated the cell growth inhibitor from the protease, and the two activities have been shown to be distinct and non-overlapping. The additional purification increased the specific biological activity of the CeReS preparation by approximately two-fold. The major inhibitory fraction that eluted from the DEAE column was further analyzed by tricine-SDS-PAGE and microbore reverse phase HPLC and shown to be homogeneous in nature. Two other fractions separated by DEAE HPLC, also devoid of protease activity, were shown to be inhibitory to cell proliferation and most likely represented modified relatives of the CeReS inhibitor. The highly purified CeReS was chemically characterized for amino acid and carbohydrate composition and the role of the carbohydrate in cell proliferation inhibition, stability, and protease resistance was assessed.

An antiproliferative factor from interstitial cystitis patients is a frizzled 8 protein-related sialoglycopeptide

“…Although other potent sialylated small glycopeptide growth inhibitors have been isolated from serum or brain of normal mammals and shown to inhibit proliferation of both normal and malignant cells from a variety of tissues (21,22), no structural data are available for any of these natural growth inhibitors, and their relationship to frizzled-related proteins or any specific signaling pathway(s) has not been determined. APF is therefore the first of this class of growth inhibitors to be completely characterized, as well as the first to be synthesized.…”