The Molecular Weights of Vertebrate Histones Exploiting a Modified Sodium Dodecyl Sulfate Electrophoretic Method

Histones have been analyzed by use of sodium dodecyl sulfate gel electrophoresis. A standard curve of histone mobility versus the logarithm of molecular weight was obtained and it was found to be different from the standard protein curve commonly used for molecular weight determination with this technique. One histone fraction (the lysine-rich histone) consists of two groups of molecules differing in molecular weight by approximately 1000. All the other histone fractions are homogenous with respect to molecular weight. The molecular weights of lysine-rich histones vary somewhat in different phylogenetic orders whereas the molecular weights of the other histones are constant in all vertebrates with the sole exception of histone F2b which has a somewhat smaller molecular weight in fish. The observations are correlated with recent observations on the mobility of these histones in a pH 2.7 electrophoretic system in the absence of sodium dodecyl sulfate (Panyim, S., Bilek, D. and Chalkley, R., J. Biol. Chem., 246, 4206 (1971)).