title: Kinetics of inhibition of ribonuclease A by Pholiota Nameko polysaccharide.
abstract: Pholiota nameko polysaccharide (PNPS-1) has been isolated and purified by enzyme hydrolysis, hot water extraction, ethanol precipitation, ion-exchange chromatography and gel-filtration column chromatography. The inhibition of bovine pancreas ribonuclease (RNase A) by PNPS-1 has been studied to elucidate the mechanism responsible for the decreased activity. PNPS-1 was effective in a linear mixed-type inhibition as suggested from the Lineweaver-Burk plot, Dixon plot and their replots. The values of K(i) and alphaK(i) were estimated as 299.92 and 545.71 microM, respectively. The alphaK(i) was greater than K(i) indicating that noncompetitive inhibition was predominant over competitive inhibition.
authors.affiliation: Tianjin Key Laboratory of Food Nutrition and Safety, Faculty of Food Engineering and Biotechnology, Tianjin University of Science and Technology, Tianjin, PR China.
authors.forename: Haiping
authors.initials: H
authors.lastname: Li
authors.forename: Shuo
authors.initials: S
authors.lastname: Wang
mesh_terms: D000363:Agaricales / Q000737:chemistry*; D000818:Animals; D001667:Binding, Competitive; D002417:Cattle; D004791:Enzyme Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D007700:Kinetics; D011134:Polysaccharides / Q000302:isolation & purification / Q000494:pharmacology*; D012259:Ribonuclease, Pancreatic / Q000037:antagonists & inhibitors*
chemical_list: D004791:Enzyme Inhibitors; D011134:Polysaccharides; D012259:Ribonuclease, Pancreatic