Amino acid sequence of the COOH-terminal portion of the arginine-lysine-rich histone of calf thymus.

1. Highly purified arginineand lysine-rich histone was maleylated and then hydrolyzed with trypsin. A large amount of precipitate approximating 35% of the histone appeared during the demaleylation procedure. The precipitate was separated into four fractions on a Sephadex G-50 column and one fraction, tryptic peptide II from the maleylated histone, was found to be the COOH-terminal portion of the histone by analysis of residues released by carbox.ypeptidases A and B. 2. The sequence of the 48 residues in this fragment determined by sequence analysis and overlapping fragments of tryptic, peptic, and thermolysin digestion products is His-LeuGin-Leu-Ala-Ile-Arg-Asn-AspGlu Glu Leu Asn Lys Leu Leu-Gly-Lys-Val-Thr-Ile-AlaGln-Gly-Gly-Val-Leu-ProAsn-Ile-Gln-Ala-ValLeu Leu -Pro Lys Lys -Thr Glu Ser His-His-Lys-Ala-Lys-Gly-Lys.