Enhanced activity of horseradish peroxidase in Langmuir-Blodgett films of phospholipids

Thais F. Schmidt, Luciano Caseli*, Tapani Viitala, Osvaldo N. Oliveira

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

70 Citations (Scopus)

Abstract

The immobilization of enzymes in nanostructured films has potential applications, e.g. in biosensing, for which the activity may not only be preserved, but also enhanced if optimized conditions are identified. Optimization is not straightforward because several requirements must be fulfilled, including a suitable matrix and film-forming technique. In this study, we show that horseradish peroxidase (HRP) has its activity enhanced when immobilized in Langmuir-Blodgett (LB) films, in conjunction with dipalmitoylphosphatidylglycerol (DPPG). Incorporation of HRP into a DPPG monolayer at the air-water interface was demonstrated with compression isotherms, and Polarization-Modulation Infrared Reflection Absorption Spectroscopy (PM-IRRAS). From the PM-IRRAS data, we inferred that HRP was not denatured when adsorbed on a pre-formed, low pressure DPPG monolayer. A change in orientation was induced by the phospholipid matrix, with the amide C{double bond, short}O and NH groups from HRP being oriented perpendicular to the surface, parallel to the DPPG acyl chains, i.e. the α-helix was inserted into the monolayer. The mixed DPPG-HRP monolayer could be transferred onto solid supports, to which HRP activity was ca. 23% higher than in solution. The control of molecular architecture and choice of a suitable phospholipid matrix allowed HRP-containing LB films to be used in sensing peroxide.

Original languageEnglish
Pages (from-to)2291-2297
Number of pages7
JournalBiochimica et Biophysica Acta - Biomembranes
Volume1778
Issue number10
DOIs
Publication statusPublished - Oct 2008
Externally publishedYes
MoE publication typeA1 Journal article-refereed

Keywords

  • Air-water interface
  • Cell membrane
  • Enzyme activity
  • Horseradish peroxidase
  • Langmuir monolayer
  • Langmuir-Blodgett film

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