Connelly P R, Gill S J, Miller K I, Zhou G, van Holde K E
Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309-0215.
Biochemistry. 1989 Feb 21;28(4):1835-43. doi: 10.1021/bi00430a061.
Employment of high-precision thin-layer methods has enabled detailed functional characterization of oxygen and carbon monoxide binding for (1) the fully assembled form with 70 binding sites and (2) the isolated chains with 7 binding sites of Octopus dofleini hemocyanin. The striking difference in the cooperativities of the two ligands for the assembled decamer is revealed through an examination of the binding capacities and the partition coefficient, determined as functions of the activities of both ligands. A global analysis of the data sets supported a two-state allosteric model assuming an allosteric unit of 7. Higher level allosteric interactions were not indicated. This contrasts to results obtained for arthropod hemocyanins. Oxygen and carbon monoxide experiments performed on the isolated subunit chain confirmed the presence of functional heterogeneity reported previously [Miller, K. (1985) Biochemistry 24, 4582-4586]. The analysis shows two types of binding sites in the ratio of 4:3.
采用高精度薄层方法能够对太平洋巨型章鱼血蓝蛋白进行详细的功能表征，包括：（1）具有70个结合位点的完全组装形式，以及（2）具有7个结合位点的分离链。通过检查结合容量和分配系数（其作为两种配体活性的函数测定），揭示了两种配体对组装十聚体的协同性存在显著差异。对数据集的全局分析支持了一个双态别构模型，该模型假设别构单元为7。未表明存在更高级别的别构相互作用。这与节肢动物血蓝蛋白的结果形成对比。在分离的亚基链上进行的氧气和一氧化碳实验证实了先前报道的功能异质性的存在[米勒，K.（1985年）《生物化学》24卷，4582 - 4586页]。分析表明存在比例为4:3的两种结合位点。
