Giardina B, Galtieri A, Lania A, Ascenzi P, Desideri A, Cerroni L, Condo S G
Institute of Chemistry, Faculty of Medicine, Catholic University, Rome, Italy.
Biochim Biophys Acta. 1992 Sep 23;1159(2):129-33. doi: 10.1016/0167-4838(92)90016-7.
The functional and spectroscopic (EPR and absorbance) properties of the adult loggerhead sea turtle (Caretta caretta) hemoglobin have been studied with special reference to the action of allosteric effectors and temperature. Present results indicate that turtle Hb displays a very low O2 affinity and a very small sensitivity to allosteric effectors and temperature. Furthermore, the amplitude of the Bohr effect for O2 binding is strongly reduced. In parallel, EPR and absorbance spectroscopic properties of the nitrosylated derivative of turtle Hb suggest that the hemoprotein is in a low-affinity conformation, even in the absence of allosteric effectors. These findings suggest the existence of unusual molecular mechanisms modulating the basic reaction of Hb with O2, which may be linked to specific physiological needs related to the diving behavior of the turtle.
对成年蠵龟（Caretta caretta）血红蛋白的功能和光谱特性（电子顺磁共振和吸光度）进行了研究，特别关注变构效应剂和温度的作用。目前的结果表明，海龟血红蛋白对氧气的亲和力非常低，对变构效应剂和温度的敏感性非常小。此外，氧气结合的波尔效应幅度大幅降低。同时，海龟血红蛋白亚硝基化衍生物的电子顺磁共振和吸光光谱特性表明，即使在没有变构效应剂的情况下，血红蛋白也处于低亲和力构象。这些发现表明存在调节血红蛋白与氧气基本反应的异常分子机制，这可能与海龟潜水行为相关的特定生理需求有关。
