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 Mg 2+ and Al 3+ 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.

Starch Biocatalyst Based on α-Amylase-Mg/Al-Layered Double Hydroxide Nanohybrids

“…These results are comparable to those obtained by several authors where high irreversibility in the adsorption process of enzymes on LDH was reported. For the immobilization of aminopeptidase on a MgAl–LDH, Frey and co-workers suggested a very strong and irreversible association between the enzyme and the LDH under the conditions tested . Forano and co-workers did not observe an effective enzyme release, except when the biohybrid enzyme/LDH material was stirred in buffered solution .…”

Functionalized layered double hydroxides for innovative applications

“…330,331 In addition to their interlayer sites, studies indicated that their outer surface can also be active sites to immobilize drug molecules. 332,333 2D LDHs are well known for their peculiar characteristics like good biocompatibility, anion exchange capacity, high chemical stability, and pH-dependent solubility. 327 These merits make them attractive and safe carriers for drug delivery and controlled release systems in biomaterial fields.…”

Facile Fabrication of Flowerlike Natural Nanotube/Layered Double Hydroxide Composites as Effective Carrier for Lysozyme Immobilization

“…Halloysite nanotubes (HNTs), one predominant form with a hollow tubular structure in the submicrometer range, were found to be a viable and inexpensive nanoscale container for the encapsulation of biologically active molecules. − Two-dimensional inorganic solids, such as layered double hydroxide (LDH), also defined as anionic clays, are considered more biocompatible and nontoxic than other inorganics, which makes them very appropriate for the immobilization of anions and biomolecules. − The above reports on the immobilization of enzymes with HNTs or LDH demonstrated the production of retentively active, catalytic and recyclable materials. However, the amount and activity of enzymes immobilized on HNTs or LDH by the adsorption method is very low, which has a direct effect on the catalytic efficiency of the unit mass of a biocomposite.…”