Histone 5 from carp erythrocytes.

Histone 5 (H5) has been isolated from carp (Cyprinus carpio) erythrocytes and identified by its amino acid composition. It was found in very small relative amounts, despite the use of either 50 mM sodium bisulfite or 1.0 mM phenylmethylsulfonyl fluoride to inhibit endogenous protease activity. Carp H5 differed significantly from H5's of other lower vertebrates in its amino acid composition, position of elution from Amberlite CG-50 ion-exchange columns, and its unusually high electrophoretic mobility. The extensive quantitative and qualtitative variability of H5 from different species must be reconciled with the presumed functional homology of these cells.