Purification and characterization of rat parotid glycosylated, basic and acidic proline-rich proteins.
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).
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Department of Microbiology and Immunology, Medical College of Pennsylvania, Philadelphia 19129, USA.
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D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002241:Carbohydrates / Q000032:analysis; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D006031:Glycosylation; D006863:Hydrogen-Ion Concentration; D008297:Male; D010306:Parotid Gland / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification*; D055232:Proline-Rich Protein Domains; D051381:Rats; D017208:Rats, Wistar; D012471:Salivary Proteins and Peptides / Q000737:chemistry / Q000302:isolation & purification
D000596:Amino Acids; D002241:Carbohydrates; D010455:Peptides; D012471:Salivary Proteins and Peptides