Presence of tyrosine-O-sulfate in sheep pituitary prolactin

Abstract

When the metabolically obtained ³⁵S-labelled sheep pituitary prolactin-rich fraction was subjected to chemical deglycosylation the radioactivity was retained in the immunoprecipitable prolactin. ³⁵S-labelled prolactin-rich pituitary extract was fractionated on SDS-PAGE and protein was extracted from prolactin positive bands. When the extracted ³⁵S-labelled prolactin was hydrolysed by alkali and then chromatographed on a thin layer of silica, it showed the presence of a radioactive compound which had an R_f value identical to the standard Tyr-O-SO₄ synthesized and characterized in our laboratory.