Premium
Ca 2+ Affects Physicochemical and Conformational Changes of Threadfin Bream Myosin and Actin in a Setting Model
Author(s) -
Hemung BungOrn,
Yongsawatdigul Jirawat
Publication year - 2005
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.2005.tb11500.x
Subject(s) - myosin , chemistry , actin , biophysics , circular dichroism , conformational change , disulfide bond , myosin head , myosin light chain kinase , biochemistry , crystallography , biology
The effect of Ca 2+ on physicochemical and conformational changes of threadfin bream (TB) myosin and actin during setting at 25 and 40°C was investigated. Ca 2+ ion at 10 to 100 mM induced the unfolding of myosin and actin as evident by an increase of surface hydrophobicity (S o ANS) at 40 °C. Total SH groups also decreased with an increased Ca 2+ concentration, suggesting that Ca 2+ promoted the formation of disulfide bonds during setting at 40 °C. Both hydrophobic interactions and disulfide linkages were involved in formation of myosin aggregates at 40 °C and were enhanced by addition of 10 to 100 mM Ca 2+ . Myosin Ca‐ATPase activity decreased when Ca 2+ was greater than 50 mM, indicating conformational changes of myosin head. Circular dichroism spectra demonstrated that Ca 2+ reduced the α‐helical content of myosin and actin incubated at either 25 or 40 °C. Ca 2+ induced conformational changes of TB myosin and actin incubated at 40 °C to a greater extent than at 25 °C.