Tamburrini M, Romano M, Carratore V, Kunzmann A, Coletta M, di Prisco G
Institute of Protein Biochemistry and Enzymology, Consiglio Nazionale delle Ricerche, Via Marconi 10, I-80125 Naples, Italy.
J Biol Chem. 1998 Dec 4;273(49):32452-9. doi: 10.1074/jbc.273.49.32452.
The oxygen-transport system of two species of Antarctic fishes belonging to the family Artedidraconidae, Artedidraco orianae and Pogonophryne scotti, was thoroughly investigated. The complete amino acid sequence of the alpha and beta chains of the single hemoglobins of the two species was established. The oxygen-binding properties were also investigated, and were found not to differ significantly from those shown by blood, intact erythrocytes, and unstripped hemolysates. Both hemoglobins have unusually high oxygen affinity and display a relatively small Bohr effect; the Root effect is elicited only by organophosphates and is also reduced. Remarkably, the Hill coefficient is close to one in the whole pH range, indicating absence of cooperative oxygen binding which, in A. orianae hemoglobin, could be ascribed to the subunit heterogeneity shown upon oxygen dissociation. In comparison with the other families of the suborder Notothenioidei, the oxygen-transport system of these two species of Artedidraconidae has unique characteristics, which raise interesting questions on the mode of function of a multisubunit molecule and the relationship with cold adaptation.
对南极鳕科的两种鱼类——奥氏南极鱼（Artedidraco orianae）和斯科特氏南极鱼（Pogonophryne scotti）的氧气运输系统进行了全面研究。确定了这两种鱼类单一血红蛋白的α链和β链的完整氨基酸序列。还研究了它们的氧结合特性，发现与血液、完整红细胞和未去除细胞膜的溶血产物所显示的特性没有显著差异。两种血红蛋白都具有异常高的氧亲和力，并且显示出相对较小的波尔效应；仅由有机磷酸盐引发的鲁特效应也有所减弱。值得注意的是，在整个pH范围内，希尔系数接近1，这表明不存在协同氧结合，在奥氏南极鱼血红蛋白中，这可能归因于氧解离时显示的亚基异质性。与南极鱼亚目的其他科相比，这两种南极鳕科鱼类的氧气运输系统具有独特的特征，这对多亚基分子的功能模式以及与冷适应的关系提出了有趣的问题。
