Purification of a low molecular weight calf pineal peptide controlling DNA transcription in vitro

Abstract

A low molecular factor showing high specific activity in the control DNA of transcription in vitro was isolated from aqueous ultrafiltered calf pineal gland extracts. The active factor was purified by means of Gel filtration on Sephadex G-25 and G-10, thin layer chromatography on aluminum sheet cellulose and high performance liquid chromatography using a Supelcosil LC 318 reverse phase column. The purified pineal factor was characterized as a peptide of low molecular weight (of about 1200 Dalton) containing glutamic acid, leucine, glycine, threonine and alanine in their approximate molar ratio, referred to glycine taken as 1: glycine 1, threonine 1, leucine 1, alanine 6, glutamic acid 2. Studies of the aminoacid sequence by N-terminal analysis using the automated Edman degradation procedure, were unsuccessful, suggesting the presence of a blocked NH2 group. The purified peptide appears to be different from peptide factors till now isolated from pineal gland.