Purification and partial characterization of an avian thymic hormone. Avian thymic hormone

An avian thymic hormone, originally designated the T1-antigen, was purified from chicken thymus by Sephadex G-75-40 chromatography and affinity chromatography, following enrichment by heat and pH treatments. It was characterized as an acidic polypeptide rich in phenylalanine, alanine and serine, lacking in histidine, tryptophan, methionine and cysteine, and having a blocked N-terminal amino acid. The hormone also was rich in hydrophobic amino acid residues, which gave it a propensity to form aggregates. Its molecular weight was estimated by gel electrophoresis and low speed sedimentation equilibrium to be 12-13 Kd, and by molecular sieving chromatography to be 15-16 Kd. The hormone was lacking in carbohydrates and amino sugars.