Temperature-dependent enthalpy of oxygenation in Antarctic fish hemoglobins
The effect of temperature on the oxygen-binding properties of the hemoglobins of three cold-adapted Antarctic fish species, Dissostichus mawsoni, Pagothenia borchgrevinki and Trematomus, sp., has been investigated under different pH values and buffer conditions. A clear non linear van't Hoff pl...
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ftuniaarhuspubl:oai:pure.atira.dk:publications/f3efef10-d05c-11de-a30a-000ea68e967b 2023-05-15T13:51:36+02:00 Temperature-dependent enthalpy of oxygenation in Antarctic fish hemoglobins Fago, A. Wells, R.M.G. Weber, Roy E. 1997 https://pure.au.dk/portal/da/publications/temperaturedependent-enthalpy-of-oxygenation-in-antarctic-fish-hemoglobins(f3efef10-d05c-11de-a30a-000ea68e967b).html eng eng info:eu-repo/semantics/restrictedAccess Fago , A , Wells , R M G & Weber , R E 1997 , ' Temperature-dependent enthalpy of oxygenation in Antarctic fish hemoglobins ' , Comparative Biochemistry and Physiology - Part B: Biochemistry & Molecular Biology , vol. 118 , no. 2 , pp. 319-326 . article 1997 ftuniaarhuspubl 2020-07-18T20:58:07Z The effect of temperature on the oxygen-binding properties of the hemoglobins of three cold-adapted Antarctic fish species, Dissostichus mawsoni, Pagothenia borchgrevinki and Trematomus, sp., has been investigated under different pH values and buffer conditions. A clear non linear van't Hoff plot (logP(50) vs 1/T) of D. mawsoni hemoglobin indicates that the enthalpy of oxygenation (slope of the plot) is temperature dependent and that at high temperatures oxygen-binding becomes less exothermic. Nearly linear relationships were found in the hemoglobins of the other two species. The data were fitted by non-linear least-squares analysis according to the integrated form of the van't Hoff equation, which includes a temperature-independent heat capacity change term (Delta C-p) that is omitted when linearity is assumed. As estimated from the fitting procedures, the heat capacity decreases upon oxygen binding. The degree of the temperature dependence of the heat of oxygenation observed in these hemoglobins seems to reflect the differences in their allosteric effects rather than a specific molecular adaptation to low temperatures. Moreover, this study indicates that the disagreement between literature data for the enthalpy of oxygenation in Antarctic fish hemoglobins derives from the use of the nonintegrated (linearized) form of the van't Hoff equation over different temperature ranges. The general assumption that a low heat of oxygenation in hemoglobins from polar animals represents an adaptation to the low-temperature habitat needs to be revised. (C) 1997 Elsevier Science Inc Udgivelsesdato: 1997/10 Article in Journal/Newspaper Antarc* Antarctic Aarhus University: Research Antarctic |
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Aarhus University: Research |
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ftuniaarhuspubl |
language |
English |
description |
The effect of temperature on the oxygen-binding properties of the hemoglobins of three cold-adapted Antarctic fish species, Dissostichus mawsoni, Pagothenia borchgrevinki and Trematomus, sp., has been investigated under different pH values and buffer conditions. A clear non linear van't Hoff plot (logP(50) vs 1/T) of D. mawsoni hemoglobin indicates that the enthalpy of oxygenation (slope of the plot) is temperature dependent and that at high temperatures oxygen-binding becomes less exothermic. Nearly linear relationships were found in the hemoglobins of the other two species. The data were fitted by non-linear least-squares analysis according to the integrated form of the van't Hoff equation, which includes a temperature-independent heat capacity change term (Delta C-p) that is omitted when linearity is assumed. As estimated from the fitting procedures, the heat capacity decreases upon oxygen binding. The degree of the temperature dependence of the heat of oxygenation observed in these hemoglobins seems to reflect the differences in their allosteric effects rather than a specific molecular adaptation to low temperatures. Moreover, this study indicates that the disagreement between literature data for the enthalpy of oxygenation in Antarctic fish hemoglobins derives from the use of the nonintegrated (linearized) form of the van't Hoff equation over different temperature ranges. The general assumption that a low heat of oxygenation in hemoglobins from polar animals represents an adaptation to the low-temperature habitat needs to be revised. (C) 1997 Elsevier Science Inc Udgivelsesdato: 1997/10 |
format |
Article in Journal/Newspaper |
author |
Fago, A. Wells, R.M.G. Weber, Roy E. |
spellingShingle |
Fago, A. Wells, R.M.G. Weber, Roy E. Temperature-dependent enthalpy of oxygenation in Antarctic fish hemoglobins |
author_facet |
Fago, A. Wells, R.M.G. Weber, Roy E. |
author_sort |
Fago, A. |
title |
Temperature-dependent enthalpy of oxygenation in Antarctic fish hemoglobins |
title_short |
Temperature-dependent enthalpy of oxygenation in Antarctic fish hemoglobins |
title_full |
Temperature-dependent enthalpy of oxygenation in Antarctic fish hemoglobins |
title_fullStr |
Temperature-dependent enthalpy of oxygenation in Antarctic fish hemoglobins |
title_full_unstemmed |
Temperature-dependent enthalpy of oxygenation in Antarctic fish hemoglobins |
title_sort |
temperature-dependent enthalpy of oxygenation in antarctic fish hemoglobins |
publishDate |
1997 |
url |
https://pure.au.dk/portal/da/publications/temperaturedependent-enthalpy-of-oxygenation-in-antarctic-fish-hemoglobins(f3efef10-d05c-11de-a30a-000ea68e967b).html |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Fago , A , Wells , R M G & Weber , R E 1997 , ' Temperature-dependent enthalpy of oxygenation in Antarctic fish hemoglobins ' , Comparative Biochemistry and Physiology - Part B: Biochemistry & Molecular Biology , vol. 118 , no. 2 , pp. 319-326 . |
op_rights |
info:eu-repo/semantics/restrictedAccess |
_version_ |
1766255582997643264 |