Peptides of neuro-intermediate lobe of hog pituitary gland

Abstract

Desiccated posterior pituitary tissue, containing between 3 and 4% peptides, was subjected to procedures involving extraction, precipitation by organic solvents, adsorption on charcoal, and dinitrophenylation. Certain of the resulting crude peptide fractions were subsequently resolved by chromatography on celite, silicic acid, cellulose powder, and paper to yield some 30 different DNP-peptides, representing a third of the initial pepetide material. The purity of the new compounds was established by column and paper chromatography and paper electrophoresis, and by the fact that each yielded only one species of fully-substituted DNP-amino acid on hydrolysis. The peptides were individually characterized with respect to qualitative amino acid composition, identity of the N-terminal residue, peptide chain length, and abundance in the original desiccated tissue. Autolytic processes, prior to, or during the initial extraction of the pituitary powder, were not considered adequate to account for the high concentrations and diversity of the peptides found in the protein-free extracts.