Temperature sensitivity of calcium binding for parvalbumins from Antarctic and temperate zone teleost fishes
| Autor: | Jeffrey R. Erickson, Bruce D. Sidell, Timothy S. Moerland |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Isothermal microcalorimetry
Physiology Climate Parvalbumins Cyprinidae Analytical chemistry Antarctic Regions chemistry.chemical_element Calorimetry Chaenocephalus aceratus Calcium Binding Competitive Biochemistry Cyprinus Mole Animals Carp Molecular Biology biology Ecology Calcium-Binding Proteins Osmolar Concentration Fishes Temperature biology.organism_classification Dissociation constant chemistry Thermodynamics Bass |
| Zdroj: | Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology. 140:179-185 |
| ISSN: | 1095-6433 |
| DOI: | 10.1016/j.cbpb.2004.12.001 |
| Popis: | Parvalbumin (PV) is a soluble calcium-binding protein that is especially abundant in fast-twitch muscles of fish and other lower vertebrates. Despite its prevalence in ectothermic taxa, few data address the effects of temperature on PV binding function. In this study, calcium dissociation constants ( K D ) were measured as a function of temperature (0–25 °C) for PV from two Antarctic ( Gobionotothen gibberifrons and Chaenocephalus aceratus ) and two temperate zone fish species ( Cyprinus carpio and Micropterus salmoides ). Measurements by fluorometric competitive binding assay show that K D values for PVs from the Antarctic species were significantly higher at all assay temperatures and were less sensitive to temperature relative to carp and bass. However, estimates of K D are fundamentally similar for PVs from the Antarctic and temperate zone species when examined at their native physiological temperature. Variation in pH and ionic strength within a physiologically relevant range had only modest effects on K D . Thermodynamics of calcium binding to PV from G . gibberifrons and C . carpio was measured by isothermal microcalorimetry. When measured at 15 °C, the Gibbs free energy change (Δ G ) was significantly greater for calcium binding to PV from G . gibberifrons than from carp (−43.4±1.5 kJ mol −1 and −46.6±3.0 kJ mol −1 , respectively), and the relative contribution of entropy to Δ G for calcium binding to PV from the Antarctic species was about twice that of carp (Δ S =16.0±0.8 J °C −1 mol −1 for G . gibberifrons ; Δ S =7.5±0.8 J °C −1 mol −1 for C . carpio ). |
| Databáze: | OpenAIRE |
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