Thermal Transitions in Myosin‐ANS Fluorescence and Gel Rigidity

Abstract

ABSTRACT Thermal transitions (Tr) in myosin were monitored during constant rate heating with a thermal scanning rigidity monitor (TSRM) and a fluorescent probe, 1‐anilino‐naphthalene‐8‐sulfonate (ANS). The Tr values from fluorescent probe measurements were 37°C, 44°C, and 44°C for tilapia, rabbit, and chicken myosin‐ANS, respectively. Three Tr values at 43°, 49°C, and 55°C were observed in TSRM measurements of tilapia myosin gelation, whereas a single Tr was observed in rabbit and chicken gelation at 48°C and 49°C, respecitvely. In tilapia myosin, KCl concentration and pH significantly influenced the TSRM but not the fluorescence thermograms. These results indicated that a prerequisite change occurred in the hydrophobic character of myosin just prior to the onset of gelation.