title: Partial purification and characterization of a polymorphic protein (Pa) in human parotid saliva.
abstract: A polymorphic acidic protein (Pa) has been isolated from human parotid saliva by the use of ion-exchange and gel filtration chromatography. Following these purification procedures, analytical anionic polyacrylamide disc gel electrophoresis revealed a single stainable band. Amino acid analysis demonstrated a protein particularly rich in proline, glutamic acid, and glycine, but with reduced amounts of threonine and no tyrosine. Only a very small percentage of carbohydrate was detected. Isoelectric focusing at pH 3-10 verified the acidic character of this protein with an isoelectric point in the range pH 3.9-4.5. Other salivary proteins called Pa-II, possibly related physiologically and genetically to the Pr system, were also partially purified and studied. Differences were noted between Pa and Pa-II proteins in molecular size and amino acid composition.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D004592:Electrophoresis, Starch Gel; D006801:Humans; D010306:Parotid Gland; D011110:Polymorphism, Genetic; D012463:Saliva / Q000032:analysis*; D012471:Salivary Proteins and Peptides / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D000596:Amino Acids; D012471:Salivary Proteins and Peptides