Abstract
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 language | English (US) |
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Pages (from-to) | 476-482 |
Number of pages | 7 |
Journal | Journal of Colloid And Interface Science |
Volume | 320 |
Issue number | 2 |
DOIs | |
State | Published - Apr 15 2008 |
Keywords
- Air-water interface
- Alkaline phosphatase
- Infrared
- Langmuir monolayers
ASJC Scopus subject areas
- Colloid and Surface Chemistry
- Physical and Theoretical Chemistry
- Surfaces and Interfaces