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Effect of annealing time of an ice crystal on the activity of type III antifreeze protein
Author(s) -
Takamichi Manabu,
Nishimiya Yoshiyuki,
Miura Ai,
Tsuda Sakae
Publication year - 2007
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2007.06164.x
Subject(s) - antifreeze protein , annealing (glass) , ice crystals , antifreeze , adsorption , thermal hysteresis , crystallography , materials science , chemistry , analytical chemistry (journal) , chromatography , thermodynamics , biochemistry , composite material , phase transition , optics , organic chemistry , physics
Antifreeze proteins (AFPs) possess a unique ability to bind to a seed ice crystal to inhibit its growth. The strength of this binding has been evaluated by thermal hysteresis (TH). In this study, we examined the dependence of TH on experimental parameters, including cooling rate, annealing time, annealing temperature and the size of the seed ice crystal for an isoform of type III AFP from notched‐fin eelpout (nfeAFP8). TH of nfeAFP8 dramatically decreased when using a fast cooling rate (0.20 °C·min −1 ). It also decreased with increasing seed crystal size under a slow cooling rate (0.01 °C·min −1 ), but such dependence was not detected under the fast cooling rate. TH was enhanced 1.4‐ and 2.5‐fold when ice crystals were annealed for 3 h at 0.05 and 0.25 °C below T m , respectively. After annealing for 2 h at 0.25 °C below T m , TH activity showed marked dependence on the size of ice crystals. These results suggest that annealing of an ice crystal for 2–3 h significantly increased the TH value of type III AFP. Based on a proposed adsorption–inhibition model, we assume that type III AFP undergoes additional ice binding to the convex ice front over a 2–3 h time scale, which results in the TH dependence on the annealing time.