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Thermodynamics Of Effector Binding To Hemocyanin: Influence Of Temperature, Ariane Pott, Michael A. Menze, Manfred K. Grieshaber
Thermodynamics Of Effector Binding To Hemocyanin: Influence Of Temperature, Ariane Pott, Michael A. Menze, Manfred K. Grieshaber
Faculty Research & Creative Activity
Hemocyanins are allosterically regulated oxygen carriers freely dissolved in the blood of many crustaceans. The natural modulator urate accumulates under hypoxic conditions in the hemolymph of Homarus vulgaris, and increases the oxygen affinity of the respiratory pigment. Other non-physiological effectors such as caffeine, dimethylxanthines and methylxanthines are also known to modulate the oxygen-binding properties of hemocyanin. In order to gain insight into the thermodynamic driving forces of these interactions we analyzed the binding of several urate analogs to dodecameric hemocyanin at different temperatures by employing isothermal titration calorimetry (ITC). All investigated non-physiological effectors including caffeine, dimethylxanthines and methylxanthines bind exothermically …
Binding Of Urate And Caffeine To Hemocyanin Of The Lobster Homarus Vulgaris (E.) As Studied By Isothermal Titration Calorimetry †, Michael A. Menze, Nadja Hellmann, Heinz Decker, Manfred K. Grieshaber
Binding Of Urate And Caffeine To Hemocyanin Of The Lobster Homarus Vulgaris (E.) As Studied By Isothermal Titration Calorimetry †, Michael A. Menze, Nadja Hellmann, Heinz Decker, Manfred K. Grieshaber
Faculty Research & Creative Activity
Hemocyanin serves as an oxygen carrier in the hemolymph of the European lobster Homarus Vulgaris. The oxygen binding behavior of the pigment is modulated by metabolic effectors such as lactate and urate. Urate and caffeine binding to 12-meric hemocyanin (H. Vulgaris) was studied using isothermal titration calorimetry (ITC). Binding isotherms were determined for fully oxygenated hemocyanin between pH 7.55 and 8.15. No pH dependence of the binding parameters could be found for either effector. Since the magnitude of the Bohr effect depends on the urate concentration, the absence of any pH dependence of urate and caffeine binding to oxygenated hemocyanin …