title: A novel catalysis by porcine pepsin in debranching guar galactomannan.
abstract: BACKGROUND
  Pepsin (porcine stomach mucosa, E.C. 3.4.23.1), an acid protease catalyzes the hydrolysis (debranching) of guar galactomannan (GG), a co-polymer of mannose and galactose residues thereby showing its non-specific catalysis towards glycosidic substrates.
  
  
  CONCLUSIONS
  Use of non-specific inhibitors, chemical modification agents and peptide mapping of native and GG--bound pepsin upon proteolytic digestion with Staphylococcus aureus V8 protease revealed the involvement of Asp(138) residue in the catalysis, which was confirmed by computational modelling studies.
  
  
  CONCLUSIONS
  Here we show a novel mode of catalysis (other than proteolysis) by porcine pepsin with a different active site residue.
authors: Department of Biochemistry and Nutrition, Central Food Technological Research Institute, Council of Scientific and Industrial Research, Mysore 570 020, India.
authors: Mysore S
authors: MS
authors: Shobha
authors: Department of Protein Chemistry and Technology, Central Food Technological Research Institute, Council of Scientific and Industrial Research, Mysore 570 020, India.
authors: Lalitha R
authors: LR
authors: Gowda
authors: Department of Biochemistry and Nutrition, Central Food Technological Research Institute, Council of Scientific and Industrial Research, Mysore 570 020, India. Electronic address: tharanathan@yahoo.co.uk.
authors: Rudrapatam N
authors: RN
authors: Tharanathan
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002384:Catalysis; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D018360:Crystallography, X-Ray; D031293:Cyamopsis / Q000737:chemistry*; D005690:Galactose / Q000031:analogs & derivatives; D008351:Mannans / Q000378:metabolism*; D062105:Molecular Docking Simulation; D008969:Molecular Sequence Data; D063347:Native Polyacrylamide Gel Electrophoresis; D010434:Pepsin A / Q000737:chemistry / Q000378:metabolism*; D010449:Peptide Mapping; D017386:Sequence Homology, Amino Acid; D013552:Swine
chemical_list: D008351:Mannans; C012990:galactomannan; D010434:Pepsin A; D005690:Galactose
keywords: Active site; Docking; Guar galactomannan; Non-specificity; Peptide mapping; Porcine pepsin