Rodewald K, Oberthür W, Braunitzer G
Biol Chem Hoppe Seyler. 1987 Jul;368(7):795-805. doi: 10.1515/bchm3.1987.368.2.795.
Some fish are warm-bodied, e.g. the bluefin tuna (Thunnus thynnus), which has a muscle temperature 12-17 degrees C higher than its environment. This endothermy is achieved by aerobic metabolism and conserved by means of a heat-exchanger system. The hemoglobins of bluefin tuna are adapted to these conditions by their endothermic oxygenation, thus contributing to the preservation of the body energy. This is a new and so far unique property of tuna hemoglobin. The primary structure of the alpha and beta chains of bluefin tuna hemoglobins is presented. The sequence was determined after enzymatic and chemical cleavages of the chains and sequencing of the peptides in gas- and liquid-phase sequencers. The alpha chains consists of 143 residues and are N-terminally acetylated. The beta chains have 146 amino acids and show two ambiguities at positions 140 and 142. The alpha chains differ from the human alpha chains in 65 amino-acid residues, the beta chains in 76. The hemoglobins of bluefin tuna, carp and man are compared and their different physiological properties are discussed in relation to the sequence data. From the primary structure of tuna hemoglobins, it is possible to propose a molecular basis for their peculiar endothermic transition from the T to the R structure.
一些鱼类是温血的，例如蓝鳍金枪鱼（Thunnus thynnus），其肌肉温度比周围环境高12 - 17摄氏度。这种恒温性通过有氧代谢实现，并借助热交换系统得以维持。蓝鳍金枪鱼的血红蛋白通过其吸热性氧合作用适应这些条件，从而有助于保存身体能量。这是金枪鱼血红蛋白一种新的且迄今为止独特的特性。文中给出了蓝鳍金枪鱼血红蛋白α链和β链的一级结构。该序列是在对链进行酶切和化学裂解，并在气相和液相测序仪中对肽段进行测序后确定的。α链由143个残基组成，N端被乙酰化。β链有146个氨基酸，在第140和142位存在两个模糊位点。蓝鳍金枪鱼的α链与人类α链在65个氨基酸残基上不同，β链与人类β链在76个氨基酸残基上不同。对蓝鳍金枪鱼、鲤鱼和人类的血红蛋白进行了比较，并结合序列数据讨论了它们不同的生理特性。从金枪鱼血红蛋白的一级结构出发，有可能为其从T结构到R结构的特殊吸热转变提出分子基础。
