Tyrosinase enzyme Langmuir monolayer: Surface chemistry and spectroscopic study

Suraj Paudyal, Shiv K. Sharma, Rafael L.C.G. da Silva, Keenan J. Mintz, Piumi Yasodha Liyanage, Abdulrahman O. Al-Youbi, Abdulaziz S. Bashammakh, Mohammad S. El-Shahawi, Roger M. Leblanc

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

This study investigates the surface chemistry properties of the tyrosinase enzyme Langmuir monolayer at air-aqueous interface using sodium chloride in the subphase to induce the surface activity of the enzyme. Investigation of surface packing and stability of the tyrosinase Langmuir monolayer were performed using surface chemistry experiments while spectroscopic analysis was done to study enzyme conformation. It was found that the tyrosinase enzyme forms a fluid film at air-aqueous interface with good stability as shown by compression-decompression cycles experiments and stability measurements at various surface pressures. UV-vis absorption and fluorescence measurements at different surface pressures revealed that the Langmuir monolayer has good homogeneity with no evidence of aggregates during compression. To gain insight on the conformation of tyrosinase Langmuir monolayer p-polarized infrared-reflection absorption spectroscopy was used. It was found that at high surface pressures the predominant secondary structures were β-sheets while at lower surface pressure both α -helices and β-sheets were present. The circular dichroism spectra were obtained by transferring the Langmuir monolayer at 10 mN.m−1 to a solid quartz support (Langmuir-Blodgett film, LB film), which showed that the major conformation present were α-helices. Images from the immobilized LB films were obtained using atomic force microscopy which showed homogenous and regular deposition with a mean thickness ranging from 3 to 4 nm.

Original languageEnglish (US)
Pages (from-to)254-263
Number of pages10
JournalJournal of Colloid And Interface Science
Volume564
DOIs
StatePublished - Mar 22 2020
Externally publishedYes

Keywords

  • Infrared reflection-absorption spectroscopy
  • Langmuir monolayer
  • Langmuir-Blodgett film
  • Surface chemistry
  • Tyrosinase

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry

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  • Cite this

    Paudyal, S., Sharma, S. K., da Silva, R. L. C. G., Mintz, K. J., Liyanage, P. Y., Al-Youbi, A. O., Bashammakh, A. S., El-Shahawi, M. S., & Leblanc, R. M. (2020). Tyrosinase enzyme Langmuir monolayer: Surface chemistry and spectroscopic study. Journal of Colloid And Interface Science, 564, 254-263. https://doi.org/10.1016/j.jcis.2019.12.118