Controlling the molecular architecture of lactase immobilized in Langmuir-Blodgett films of phospholipids to modulate the enzyme activity

Autor(es)

Ayoub, Fabio de Paula ; Caseli, Luciano

• Tipo de documento: Artigo Científico
• Fonte: COLLOIDS AND SURFACES B-BIOINTERFACES; v. 150, p. 8-14, FEB 1 2017.
• Citações Web of Science: 10

Resumo

In this present work, the adsorption of the enzyme lactase onto Langmuir monolayers of the phospholipid dimyristoylphosphatidic acid (DMPA) was investigated and characterized with surface pressure-area isotherms, surface potential-area isotherms and polarization-modulated infrared reflection-absorption spectroscopy (PM-IRRAS). The adsorption of the enzyme at the air-water interface expanded the lipid monolayer and increased the film compressibility at high surface pressures. Amide bands in the PM-IRRAS spectra were identified, with the C-N and C=O dipole moments lying parallel to the monolayer plane, revealing that the structuring of the enzyme into beta-sheets was kept in the mixed monolayer. The enzyme-lipid films were transferred from the floating monolayer to solid supports as Langmuir-Blodgett (LB) films and characterized with fluorescence spectroscopy and atomic force microscopy. The catalytic activity of the films was measured and compared to the homogenous medium. The enzyme accommodated in the LB films preserved more than 80% of the enzyme activity after 20 days, in contrast for the homogeneous medium, which preserved less than 60% of the enzyme activity. The method presented in this present work not only allows for an enhanced catalytic activity toward lactose, but also can help explain why certain film architectures exhibit better performance. (C) 2016 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 15/23446-0 - Superfícies inteligentes nanoestruturadas e bioinspiradas: investigação de interações em modelos de membrana e produção de dispositivos para biossensores e análise ambiental.
• Beneficiário: Luciano Caseli
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 14/12557-2 - EMU concedido no processo 2013/14262-7; reômetro interfacial
• Beneficiário: Osvaldo Novais de Oliveira Junior
• Modalidade de apoio: Auxílio à Pesquisa - Programa Equipamentos Multiusuários