[Histone H1 from the herring Clupea harengus pallasi testis structurally resembling histone H5].

Erythrocyte- and testis-specific fractions of the lysine-rich histone of herring Clupea harengus pallasi were studied. Electrophoretically purified fractions were cleaved at residues of tyrosine and phenylalanine. The fragments thus obtained and intact proteins were investigated by the method of incomplete succinylation which permitted one to determine the number of lysine residues, the total number of arginine and histidine residues and the molecular length of polypeptides. It has been found that the testis-specific fraction has in its C-terminal half of the molecule 15 arginine residues and a high proportion of basic amino acid residues (0,49) and thereby resembles the histone H5 of birds and fishes. The N-terminal half of this fraction however is close to the somatic variants of lysine-rich histones by the number of arginine residues and by the proportion of basic amino acid residues. To the author's knowledge, the testis-specific fraction of the lysine-rich histone in fishes are described for the first time.