Adsorption Kinetics of Type-III Antifreeze Protein on Ice Crystal Surfaces

Langmuir. 2023 Jun 27;39(25):8612-8622. doi: 10.1021/acs.langmuir.3c00299. Epub 2023 Jun 9.

Abstract

The spatio-temporal distribution of type-III antifreeze protein (AFP-III) molecules labeled with fluorescent isocyanate (FITC) was visualized at the interfaces between ice and solutions with an FITC-labeled AFP-III (F-AFP-III) concentration of 20-800 μg/mL by fluorescence microscopy. The number density of F-AFP-III on the surface of ice microcrystals was calculated from the calibrated fluorescence intensity. The adsorption of F-AFP-III molecules on the ice crystal surfaces proceeded at a finite rate and then reached the saturation level. The time course of the number density of adsorbed F-AFP-III molecules could be well represented by Langmuir's model. The characteristic adsorption time of F-AFP-III, the adsorption coefficient k1 = (0.5 ± 0.05) × 10-4 (μg/mL)-1 s-1, and the desorption coefficient k2 = 0.005 ± 0.002 s-1 were determined using the Langmuir's model and obtained experimental data. We found that the adsorption of F-AFP-III could have different kinetics depending on the solution conditions and the type of fluorescence molecules conjugated with AFP-III.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adsorption
  • Antifreeze Proteins / chemistry
  • Fluorescein-5-isothiocyanate
  • Ice*
  • Kinetics
  • alpha-Fetoproteins*

Substances

  • Ice
  • Fluorescein-5-isothiocyanate
  • alpha-Fetoproteins
  • Antifreeze Proteins