Rat osseous plate alkaline phosphatase as Langmuir monolayer-An infrared study at the air-water interface

Luciano Caseli, Douglas C. Masui, Rosa P.M. Furriel, Francisco A. Leone, Maria E.D. Zaniquelli, Jhony Orbulescu, Roger M. Leblanc

Research output: Contribution to journalArticle

23 Scopus citations


A glycosylphosphatidylinositol (GPI)-anchored enzyme (rat osseous plate alkaline phosphatase-OAP) was studied as monolayer (pure and mixed with lipids) at the air-water interface. Surface pressure and surface potential-area isotherms showed that the enzyme forms a stable monolayer and exhibits a liquid-expanded state even at surface pressure as high as 30 mN m-1. Isotherms for mixed dimyristoylphosphatidic acid (DMPA)-OAP monolayer showed the absence of a liquid-expanded/liquid-condensed phase transition as observed for pure DMPA monolayer. In both cases, pure or mixed monolayer, the enzyme preserves its native conformation under compression at the air-water interface as observed from in situ p-polarized light Fourier transform-infrared reflection-absorption spectroscopic (FT-IRRAS) measurements. Changes in orientation and conformation of the enzyme due to the presence or absence of DMPA, as well as due to the surface compression, are discussed.

Original languageEnglish (US)
Pages (from-to)476-482
Number of pages7
JournalJournal of Colloid And Interface Science
Issue number2
StatePublished - Apr 15 2008



  • Air-water interface
  • Alkaline phosphatase
  • Infrared
  • Langmuir monolayers

ASJC Scopus subject areas

  • Colloid and Surface Chemistry
  • Physical and Theoretical Chemistry
  • Surfaces and Interfaces

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