Condò S G, Coletta M, Cicchetti R, Argentin G, Guerrieri P, Marini S, el-Sherbini S, Giardina B
Department of Experimental Medicine and Biochemical Sciences, University of Rome Tor Vergata, Italy.
Biochem J. 1992 Mar 1;282 ( Pt 2)(Pt 2):595-9. doi: 10.1042/bj2820595.
The equilibrium O2-binding properties of the hybrid haemoglobin (Hb) present in vivo in erythrocytes from mule and of its parent Hbs from horse and donkey were compared with special reference to the effect of heterotropic ligands such as Cl-, D-glycerate 2,3-bisphosphate (DPG) and inositol hexakisphosphate. All these Hbs display a decreased effect by polyphosphates, confirming that what has been observed for horse Hb [Giardina, Brix, Clementi, Scatena, Nicoletti, Cicchetti, Argentin & Condò (1990) Biochem. J. 266, 897-900] is common to other equine species, at least from a qualitative standpoint. However, different quantitative aspects can be detected, which can be accounted for by a different role for the two types of chain in characterizing the binding free energy for the various heterotropic effectors. In particular, it is shown that the binding mode of DPG and inositol hexakisphosphate displays different features since long-range effects can be observed clearly for inositol hexakisphosphate but not for DPG. In general terms, in spite of a different intrinsic O2 affinity, the modulation of functional properties by third ligands leads these Hbs to behave, under physiological conditions, similarly to human HbA. It might represent an interesting example of how different species with similar functional needs find different ways to produce a similar functional behaviour.
比较了骡红细胞中存在的杂合血红蛋白（Hb）及其来自马和驴的亲本Hb在体内的平衡氧结合特性，特别参考了异质性配体如Cl-、二磷酸甘油酸（DPG）和肌醇六磷酸的影响。所有这些Hb都显示出多磷酸盐的作用减弱，这证实了在马Hb中观察到的现象[贾尔迪纳、布里克斯、克莱门蒂、斯卡泰纳、尼科莱蒂、西凯蒂、阿根廷和孔多（1990年）《生物化学杂志》266卷，897 - 900页]至少从定性角度来看在其他马种中是常见的。然而，可以检测到不同的定量方面，这可以通过两种类型的链在表征各种异质性效应物的结合自由能方面的不同作用来解释。特别是，已表明DPG和肌醇六磷酸的结合模式显示出不同的特征，因为对于肌醇六磷酸可以清楚地观察到远程效应，而对于DPG则不然。一般来说，尽管具有不同的内在氧亲和力，但第三配体对功能特性的调节使这些Hb在生理条件下的行为类似于人HbA。这可能代表了一个有趣的例子，说明具有相似功能需求的不同物种如何找到不同的方式来产生相似的功能行为。
