Polyacrylamide gel electrophoresis of human salivary histidine-rich-polypeptides

A method of polyacrylamide gel electro-phoresis for examining histidine-rich-polypep-tides in human saliva is described. Comparison is made to several commonly used electrophor-retic techniques. The described method allows for the resolution of seven histidine-rich-poly-peptide fractions and is convenient and quite reproducible. J Dent Res 56(9): 1115-1118 September 1977. Electrophoretic techniques have been widely used for analysis of the protein components of human saliva.1 It is well understood that no one electrophoretic method provides adequate in-formation on all salivary proteins. Recently several laboratories have been interested in a group of histidine-rich-polypep-tides (HRP) found in human parotid saliva.2-5 The IURP have certain biological and chemical properties which render analysis by common electrophoretic techniques deceptive. The HRP are small molecules (3,000 to 6,000 daltons) related by a degradative phenomenon.2 The ap-parent progenitor molecule (termed HRP-1) has a neutral isoelectric point and gives rise to the other HRP by a progressive breakdown. These include several extremely cationic frac-tions (pl> 10).2 We have observed that the frequently used anionic (Davis6) and cationic (Reisfeld et al.7) methods of polyacrylamide gel electrophoresis were not suitable for simultaneous examination of all HRP. We have modified another tech