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Functional behavior of tortoise hemoglobin Geochelone denticulata
M A Torsoni1, G R Stoppa, A Turra
1Universidade Braz Cubas, CEP 08773-380, Mogi das Cruzes, SP, Brazil. torsoni@yahoo.com
Brazilian Journal of Biology = Revista Brasleira De Biologia
|March 28, 2003
Summary
The hemolysate from Geochelone denticulata contains two main hemoglobin components. Its oxygen-binding properties are influenced by organic phosphates and hydrogen ions, suggesting higher oxygen capacity for survival.
Area of Science:
- Biochemistry
- Comparative Physiology
- Zoology
Background:
- The hemolysate of Geochelone denticulata exhibits complex hemoglobin composition.
- Understanding hemoglobin function is crucial for assessing oxygen transport in reptiles.
Purpose of the Study:
- To characterize the hemoglobin components and oxygen-binding properties of Geochelone denticulata.
- To compare the oxygen-carrying capacity with Geochelone carbonaria.
Main Methods:
- Ion exchange chromatography and polyacrylamide gel electrophoresis (PAGE) were used to analyze hemoglobin components.
- Gel filtration (Sephadex G-200) determined molecular mass.
- Oxygen equilibrium curves measured P50 and n50 values under varying conditions (pH, ATP, IHP).
Main Results:
- Two main hemoglobin components and three globin chains were identified.
- Hemoglobin (Hb) is tetrameric and does not polymerize.
- P50 value at pH 7.4 is 9.56 mm Hg, significantly increasing with ATP and IHP.
- Bohr effect is evident; n50 values increase with organic phosphates.
- Geochelone denticulata blood has higher hematocrit and Hb concentration than Geochelone carbonaria.
Conclusions:
- Geochelone denticulata hemoglobin's oxygenation is regulated by organic phosphates and pH.
- The functional properties of Hb and higher blood parameters suggest superior oxygen capacity in G. denticulata, ensuring animal survival.