Abstract
Human fibroblast-derived interferon-beta (IFN-β) labeled in vivo with 35S-methionine and purified to greater than 90% radiochemical purity has been used to study the effect of glycosidases on its biological activity and its molecular weight. Incubation of the radioactive interferon with the glycosidases causes a reduction in the estimated molecular weight from 23,000 to 18,000 as determined by electrophoresis on SDS-gels. There are intermediate transient sizes that are generated prior to 18,000, but not proteins are observed that are smaller than 18,000 even after prolonged incubation. The deglycosylated IFN-β (18,000) induces the antiviral state in cells in culture and inhibits the growth of cells in culture. We conclude that the carbohydrate of IFN-β is not essential for its biological activity on cells in culture.
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