title: A kinetic study of bovine haemoglobin hydrolysis by pepsin immobilized on a functionalized alumina to prepare hydrolysates containing bioactive peptides.
abstract: The hydrolysis kinetics of native and denatured haemoglobin, using pepsin immobilized on aluminium oxide, was studied in order to produce hydrolysates containing bioactive peptides. Pepsin was immobilized on acidic alumina and on 2-ethanolamine- O -phosphate (2-EAOP)-modified acidic alumina. Surface charge of the two supports was determined as a function of pH. Kinetic studies were performed at 23 degrees C in 0.1 M acetate buffer, pH 4.5. At this pH, the surface charge of the two supports was almost the same. The coating of alumina by 2-EAOP only introduced a two carbon spacer between alumina surface and the reaction medium. Adsorption on the two supports of haemoglobin, haem and peptides produced in the course of hydrolyses were compared. Fixation of 2-EAOP on a pepsin-alumina complex gave hydrolysis kinetics of urea-denatured haemoglobin close to that obtained with the same amount of pepsin in solution, but with comparatively less adsorption of peptides and complete adsorption of haem. Heterogeneous hydrolyses of haemoglobin with pepsin, immobilized on functionalized alumina, resulted in the presence of VV-haemorphin-4, VV-haemorphin-7 and neokyotorphin in the supernatants without haem, the presence of which makes further purification difficult.
authors.affiliation: Laboratorul de Biochimie, Facultatea de Biologie, Universitatea Al. I. Cuza, Iaşi, Romania.
authors.forename: Elena-Loredana
authors.initials: EL
authors.lastname: Ticu
authors.forename: Dominique
authors.initials: D
authors.lastname: Vercaigne-Marko
authors.forename: Anca
authors.initials: A
authors.lastname: Huma
authors.forename: Vlad
authors.initials: V
authors.lastname: Artenie
authors.forename: Ovidiu
authors.initials: O
authors.lastname: Toma
authors.forename: Didier
authors.initials: D
authors.lastname: Guillochon
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D000818:Animals; D002417:Cattle; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D004789:Enzyme Activation; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry; D006454:Hemoglobins / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D008422:Materials Testing; D010434:Pepsin A / Q000737:chemistry*; D010455:Peptides / Q000138:chemical synthesis*; D011492:Protein Hydrolysates / Q000138:chemical synthesis*
chemical_list: D020099:Coated Materials, Biocompatible; D004800:Enzymes, Immobilized; D006454:Hemoglobins; D010455:Peptides; D011492:Protein Hydrolysates; D010434:Pepsin A; D000537:Aluminum Oxide