Deparade M P, Glöggler K, Trommer W E
Biochim Biophys Acta. 1981 Jun 15;659(2):422-33. doi: 10.1016/0005-2744(81)90068-1.
Glyceraldehyde-3-phosphate dehydrogenase (D-glyceraldehyde-3-phosphate: NAD+ oxidoreductase (phosphorylating), EC 1.2.1.12) was isolated from a sturgeon, Huso huso, from the Caspian Sea. It is closely related to the enzyme from a Pacific sturgeon, Acipenser transmontanus, with respect to amino acid composition, steady-state kinetics and coenzyme binding. The latter, as studied by means of a spin-labeled derivative of NAD+, is negatively cooperative exhibiting a Hill coefficient of 0.84 at 12 degrees C. Two derivatives of NAD+ spin-labeled at N6 or C8 of the adenine ring were found to be active coenzymes with maximum velocities reaching 35 or 45% of the value for NAD+ itself. When more than two equivalents of either spin-labeled NAD+ are bound to the enzyme spin-spin interactions are observed in the ESR spectra. Distances between the nitroxide radicals (8--9 A) calculated from the observed splittings are in excellent agreement with data predicted from the crystal structure of the lobster enzyme when the coenzyme is bound in an anti-conformation of the adenine moiety about the glycosidic bond to all four subunits.
从里海的一种鲟鱼——欧洲鳇（Huso huso）中分离出了3-磷酸甘油醛脱氢酶（D-甘油醛-3-磷酸：NAD⁺氧化还原酶（磷酸化），EC 1.2.1.12）。就氨基酸组成、稳态动力学和辅酶结合而言，它与太平洋鲟鱼（Acipenser transmontanus）的这种酶密切相关。通过NAD⁺的自旋标记衍生物研究发现，后者具有负协同性，在12℃时希尔系数为0.84。发现在腺嘌呤环的N6或C8处自旋标记的两种NAD⁺衍生物是活性辅酶，最大速度分别达到NAD⁺自身值的35%或45%。当超过两当量的任何一种自旋标记的NAD⁺与该酶结合时，在电子顺磁共振光谱中会观察到自旋-自旋相互作用。根据观察到的分裂计算出的氮氧自由基之间的距离（8 - 9 Å），与当辅酶以腺嘌呤部分围绕糖苷键的反式构象与所有四个亚基结合时龙虾酶晶体结构预测的数据非常吻合。
