Conversion of high molecular weight CRF (corticotropin-releasing factor) or PRF (prolactin-releasing factor) into lower molecular weight forms by boiling at low pH

Abstract

Extracts (0.1 N HCl) of bovine hypophyseal stalk had 2 CRF peaks, one (CRF-A) in the void volume with Sephadex G-100 chromatography, the other more retarded (CRF-B). PRF activity of the same extracts eluted in 2 peaks from G-100, one in the void volume (PRF-A) and the other (PRF-B) between A and B CRF peaks. On rechromatography, isolated CRF-A and PRF-A remained in the void volume. However, heating to 100 C at pH 1–2 for 15 min converted CRF-A to CRF-B and PRF-A to PRF-C, which eluted after PRF-B on G-100. We conclude that CRF or PRF can be converted from high to low molecular weight forms with full retention of biological activity.