ABSTRACT
The heterogeneity and aggregation of histones at nearly neutral pH values made studies of their molecular properties difficult. Gel electrophoresis offers an extremely sensitive tool for the detection of histone aggregates, the information about their size and molecular weight is derived, in most instances, from physicochemical measurements. Refinement in the electrophoretic studies on histone heterogeneity, both natural and caused by aggregation, occurred with the introduction of polyacrylamide gel electrophoresis to this field by Reisfeld et al. The ordered part of the histone molecules, contains the hydrophobic amino acid residues and may function in more specific protein-protein interactions. The ideas about the conformation of histones associated with DNA in the nucleohistone were obtained from x-ray diffraction, infrared spectrophotometry, and deuteration studies. The significance of the asymmetry for the biological function of histones is presently unknown and is the subject of many speculations.
