期刊论文详细信息
FEBS Letters
A calorimetric study of Ca2+ binding to two major isotypes of bullfrog parvalbumin
Yamada, Kazuhiro1  Tanokura, Masaru1 
[1] Department of Physiology, Medical College of Oita, Hasama, Oita 879-56, Japan
关键词: Microcalorimetry;    Parvalbumin;    Ca2+ binding;    Mg2+ binding;    Enthalpy titration;   
DOI  :  10.1016/0014-5793(85)80763-8
学科分类:生物化学/生物物理
来源: John Wiley & Sons Ltd.
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【 摘 要 】

Microcalorimetric titrations of the two major isotypes of parvalbumin (PA1 and PA2) from bullfrog skeletal muscle with Ca2+ in the presence and absence of Mg2+ have been carried out at 25°C and pH 7.0. The observed enthalpy titration curves were analyzed by the least-squares method. The measured enthalpy changes (ΔH) of Ca2+ binding are −33.2 (PA1) and −16.3 math formula site (PA2), and the entropy changes (ΔS) are 28 (PA1) and 76 math formula per K (PA2) in the absence of Mg2+. When 5 mM Mg2+ is present, the enthalpy change of PA2 (−26.7 math formula) is about twice as large as that in the absence of Mg2+ whereas that of PA1 (−34.6 math formula) is about the same. The entropy changes are 8 (PA1) and 29 math formula per K (PA2). Both enthalpy and entropy changes are favorable for the Ca2+-binding reactions of PA1 and PA2 irrespective of the presence of Mg2+.

【 授权许可】

Unknown   

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