title: Reformation of reduced disulfide bonds of pepsinogen and pepsin: role of the phosphate group.
abstract: Reduction of the disulfide bonds in pepsinogen and pepsin with 2-mercaptoethanol eliminated the proteolytic activity of the enzyme and the potential proteolytic activity of the zymogen. Removal of the reducing agent followed by airation resulted in reformation of the disulfide bonds in the phospho-forms of pepsinogen and pepsin, but not in the dephospho-forms. To account for the role of the phosphate group in the stabilization of the native conformation even at reduced states of the zymogen and the enzyme, it is suggested that the group which is linked to the seryl residue is also linked to another amino acid residue in the form of anhydride, hydrogen bond(s), or/and ionic interaction.
mesh_terms: D000818:Animals; D002162:Camelus; D004220:Disulfides / Q000378:metabolism*; D005753:Gastric Mucosa / Q000201:enzymology; D007700:Kinetics; D008623:Mercaptoethanol / Q000494:pharmacology; D010084:Oxidation-Reduction; D010434:Pepsin A / Q000378:metabolism*; D010435:Pepsinogens / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism
chemical_list: D004220:Disulfides; D010435:Pepsinogens; D010750:Phosphoproteins; D008623:Mercaptoethanol; D010434:Pepsin A