Purification and Characterization of Rat Parotid Glycosylated, Basic and Acidic Proline-Rich Proteins

Prep Biochem. 1995 Aug;25(3):119-32. doi: 10.1080/10826069508010115.


A unique family of proline-rich proteins (PRPs) is induced in rats following prolonged isoproterenol treatment. PRPs can be divided into glycosylated (GPRP), basic (BPRP) and acidic (APRP) proline-rich proteins based on their physicochemical characteristics. Inducible rat parotid PRPs were isolated from aqueous extracts of parotid glands of isoproterenol-treated animals by sequential chromatography on columns of DEAE-Sepharose CL-6B, Sephadex G-100 and FPLC on Suprose-12 column. The GPRP showed a single homogeneous band on sodium dodecylpolyacrylamide gel electrophoresis with an estimated molecular weight of approximately 220,000. Compositional analysis of GPRP revealed that this protein contained 19.7% glutamic acid/glutamine, 28.2% proline and 9.5% glycine, and 44% carbohydrate, consisting of fucose (2.81g/100g), mannose (9.78g/100g), galactose (9.29g/100g), N-acetylglucosamine (18.03g/100g) and N-acetylgalactosamine (3.90g/100g). Basic PRPs consisted of a family of proteins with estimated molecular masses ranging from 14-45 kDa. These proteins contained 42.6% proline, 20.65% glutamic acid/glutamine and 21.33% glycine. Acidic PRPs also comprised of a family of metachromatically stained ladder of 40-60 kDa containing 29.1% proline, 21.5% glutamic acid/glutamine and 17.8% glycine. APRP were heavily glycosylated containing N-acetylglucosamine (6.34g/100g), N-acetylgalactosamine (19.04g/100g) and glucuronic acid (38.08g/100g).

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acids / analysis
  • Animals
  • Carbohydrates / analysis
  • Chromatography, Ion Exchange
  • Electrophoresis, Polyacrylamide Gel
  • Glycosylation
  • Hydrogen-Ion Concentration
  • Male
  • Parotid Gland / chemistry*
  • Peptides / chemistry
  • Peptides / isolation & purification*
  • Proline-Rich Protein Domains
  • Rats
  • Rats, Wistar
  • Salivary Proteins and Peptides / chemistry
  • Salivary Proteins and Peptides / isolation & purification


  • Amino Acids
  • Carbohydrates
  • Peptides
  • Salivary Proteins and Peptides