Human testis-specific histone TH2B: fractionation and peptide mapping.

The presence of the nonionic detergent Triton X-100 was shown to improve the resolution of the human TH2B on gel electrophoresis and on gel filtration. Total histones of human testis, including TH2B, were resolved by electrophoresis in 15% polyacrylamide gels containing 0.4% Triton X-100, 1.5 M urea, and 0.9 N acetic acid. Gel filtration on Bio-Gel P-200 in 0.4% Triton X-100, 5.0 M urea, and 0.01 N HCl permitted the purification of human TH2B from human testis and sperm in preparative amounts. The structure of human TH2B so prepared was compared to that of rat TH2B, human H2B, and rat H2B by tryptic peptide mapping. The results showed some similarities between all four proteins, but closer similarity was observed within the germ cell histone (TH2B) group and within the somatic histone (H2B) group than between histones of the same species. In addition, human TH2B and rat TH2B each contained one unique peptide absent from other histones.