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A facile method for determining ice recrystallization inhibition by antifreeze proteins
Melanie M Tomczak1, Christopher B Marshall, Jack A Gilbert
1Department of Biochemistry and the Protein Engineering Network of Centres of Excellence, Queen's University, Ont., K7L 3N6, Kingston, Canada.
Biochemical and Biophysical Research Communications
|November 19, 2003
Summary
A new method using glass capillaries quantifies antifreeze protein (AFP) ice recrystallization inhibition (RI) activity. This technique accurately determines the RI endpoint for AFPs, aiding in understanding their function in freezing processes.
Area of Science:
- Biochemistry
- Cryobiology
Background:
- Ice recrystallization stresses freeze-tolerant organisms and causes food spoilage.
- Antifreeze proteins (AFPs) inhibit ice recrystallization.
Purpose of the Study:
- To present a simple method for determining AFP ice recrystallization inhibition (RI) activity under physiological conditions.
- To establish a reproducible and archive-able assay for RI endpoint determination.
Main Methods:
- Utilized 10microl glass capillaries for AFP RI activity assays.
- Prepared serial dilutions to determine the RI endpoint concentration.
- Employed simultaneous sample alignment and viewing for efficient endpoint determination.
Main Results:
- Determined the RI endpoint for type III AFP to be 200nM.
- Successfully detected type III AFP elution from a Sephadex G-75 column using the RI assay.
- Observed unexpected RI activity in the void volume during column elution.
Conclusions:
- The capillary method provides a simple, reproducible, and archive-able means to assess AFP RI activity.
- The method facilitated the detection of AFP elution and identified unexpected behavior in size-exclusion chromatography.