title: Comparison of the properties of trypsin immobilized on 2 Celite derivatives.
abstract: Trypsin was immobilized on 2 Celite derivatives and the kinetic properties of trypsin immobilized on these derivatives were determined and compared. Celite was derivatized with organosilane to give aminopropyl-Celite (APC) and a portion of this derivative was then succinylated to give succinamidopropyl-Celite (SAPC). Trypsin was covalently immobilized on APC using glutaraldehyde to activate amino groups and on SAPC using water-soluble carbodiimide to activate surface carboxyl groups. Enzyme loadings were 13.9 and 17.8 mg ml-1 of beads on APC and SAPC, respectively. Using p-tosyl-L-arginine methyl ester as substrate, the catalyst specific activity, KMapp and kcat/KMapp were 17.8 U ml-1 of beads, 3.60 and 21.0 mM-1 min-1, respectively, for trypsin-APC as compared with 24.5 U ml-1 of beads, 3.77 and 20.3 mM-1 min-1, respectively, for trypsin-SAPC. With beta-lactoglobulin as substrate, KMapp and kcat/KMapp were 0.36 and 1.62 mM-1 min-1 for trypsin-APC and 0.54 and 1.39 mM-1 min-1 for trypsin-SAPC, respectively. The pH range for optimal activity was much larger for both immobilized forms as compared with the soluble enzyme. The optimal temperature ranges were 40-50 degrees C for trypsin-APC and 50-60 degrees C for trypsin-SAPC. The two methods of immobilization on Celite gave biocataysts with similar kinetic properties but immobilization on SAPC yielded slightly higher loadings and higher specific activities.
authors.affiliation: Department of Food Science, North Carolina State University, Raleigh 27695-7624, USA.
authors.forename: X L
authors.initials: XL
authors.lastname: Huang
authors.forename: G L
authors.initials: GL
authors.lastname: Catignani
authors.forename: H E
authors.initials: HE
authors.lastname: Swaisgood
mesh_terms: D007692:Diatomaceous Earth / Q000737:chemistry*; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D014357:Trypsin / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D004800:Enzymes, Immobilized; D007692:Diatomaceous Earth; D014357:Trypsin