title: Immobilization of the aminopeptidase from Aeromonas proteolytica on Mg2+/Al3+ layered double hydroxide particles.
abstract: A novel biomaterial formed by the immobilization of the Aminopeptidase from Aeromonas proteolytica (AAP) on synthetic Mg2+ and Al3+ ion-containing layered double hydroxide (LDH) particles was prepared. Immobilization of AAP on the LDH particles in a buffered, aqueous mixture is rapid such that the maximum loading capacity, 1×10(-9) moles of AAP/mg LDH, is achieved in a few minutes. X-ray powder diffraction of LDH samples before and after treatment with AAP indicates that the enzyme does not intercalate between the layers of LDH, but instead binds to the surface. Treatment of AAP/LDH with various amounts of salt in a buffered mixture demonstrates that between 15 and 20% of AAP can be removed from the LDH by washing the composite material in 0.2 M NaCl. However, the residual AAP remains bound to the LDH even at 1 M salt concentrations. A suspension of the AAP/LDH biomaterial in 10 mM Tricine buffered, aqueous solution (pH 8.0 and 25° C) catalyzes the hydrolysis of l-leucine-p-nitroanilide demonstrating that immobilized AAP remains available to substrate and retains its catalytic activity. Recycling experiments reveal that the AAP/LDH particles can be recovered and reused multiple times without appreciable loss of activity. This work provides the foundation for the development of materials that will function in the degradation or detection of peptide hormones or neurotoxins.
authors.affiliation: Department of Chemistry, Skidmore College, Saratoga Springs, New York 12866, USA. sfrey@skidmore.edu
authors.forename: Steven T
authors.initials: ST
authors.lastname: Frey
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Guilmet
authors.forename: Richard G
authors.initials: RG
authors.lastname: Egan
authors.forename: Alyssa
authors.initials: A
authors.lastname: Bennett
authors.forename: Sarah R
authors.initials: SR
authors.lastname: Soltau
authors.forename: Richard C
authors.initials: RC
authors.lastname: Holz
mesh_terms: D000333:Aeromonas / Q000201:enzymology*; D000537:Aluminum Oxide / Q000737:chemistry*; D000626:Aminopeptidases / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D004800:Enzymes, Immobilized / Q000737:chemistry*; D008277:Magnesium Oxide / Q000737:chemistry*; D009498:Neurotoxins / Q000737:chemistry; D036361:Peptide Hormones / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D004800:Enzymes, Immobilized; D009498:Neurotoxins; D036361:Peptide Hormones; D008277:Magnesium Oxide; D000626:Aminopeptidases; C038222:bacterial leucyl aminopeptidase; D000537:Aluminum Oxide
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