Maginniss L A, Olszowka A J, Reeves R B
Am J Physiol. 1986 Feb;250(2 Pt 2):R298-305. doi: 10.1152/ajpregu.1986.250.2.R298.
Adult sheep (Ovis aries) exhibit hemoglobin heterogeneity controlled by two autosomal alleles with codominant expression (Hb AA, AB, BB). Isoelectric points for Hb A and Hb B were 6.94 and 7.15, respectively; for Hb AB animals, the two allohemoglobins were present in equimolar concentrations (Hb A = 52%, Hb B = 48%). Dynamic O2 equilibrium curves (O2ECs) were generated for sheep whole blood at 39 degrees C using thin-film techniques. Half-saturation PO2 values (P50) at pH 7.50 were 31.3, 35.7, and 40.7 Torr for Hb AA, AB, and BB, respectively. CO2 Bohr coefficients at saturation (S) = 0.5 (delta log P50/delta pH) were similar for all phenotypes, ranging from -0.38 to -0.40. The Bohr slopes were also saturation independent between 0.2 and 0.8 S. Standard O2ECs for each phenotype were accurately fitted to three-constant third-order polynomial expressions. Sheep equilibrium curves were not isomorphic with other mammalian O2ECs (e.g., human and dog); sheep curves exhibited greater sigmoidicity. Furthermore, allohemoglobin interaction was not detected in heterozygous sheep. The blood O2 binding characteristics (P50, curve shape, and delta log PO2/delta pH) for Hb AB sheep and an experimental blood mixture containing equal proportions of Hb AA and Hb BB erythrocytes were equivalent.
成年绵羊（Ovis aries）表现出血红蛋白异质性，由两个常染色体等位基因控制，呈共显性表达（Hb AA、AB、BB）。Hb A和Hb B的等电点分别为6.94和7.15；对于Hb AB动物，两种异源血红蛋白以等摩尔浓度存在（Hb A = 52%，Hb B = 48%）。使用薄膜技术在39℃下生成了绵羊全血的动态氧平衡曲线（O2ECs）。在pH 7.50时，Hb AA、AB和BB的半饱和PO2值（P50）分别为31.3、35.7和40.7 Torr。所有表型的饱和时CO2玻尔系数（S = 0.5，δlog P50/δpH）相似，范围为-0.38至-0.40。玻尔斜率在0.2至0.8 S之间也与饱和度无关。每个表型的标准O2ECs都能准确地拟合为三常数三阶多项式表达式。绵羊的平衡曲线与其他哺乳动物的O2ECs（如人类和狗）不同构；绵羊曲线表现出更大的S形。此外，在杂合绵羊中未检测到异源血红蛋白相互作用。Hb AB绵羊以及含有等比例Hb AA和Hb BB红细胞的实验性血液混合物的血液氧结合特性（P50、曲线形状和δlog PO2/δpH）是等效的。
