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Oxygen equilibrium curves of fresh, normal human blood have been measured by new methods which allow the control of pH, pCO2, and 2,3-diphosphoglycerate and which yield higher accuracy at the extremes of saturation than was possible previously. The curve determined by these techniques lies slightly to the right of the standard curve of Roughton et al.(More)
1. The difference of pH (DeltapH) between human deoxygenated haemoglobin (Hb) and oxygenated haemoglobin (O(2)Hb) solutions when equilibrated with physiological pressures of carbon dioxide is (experimentally) much less than previously supposed.2. This smaller DeltapH is in contradiction to Wyman's (1948) theoretical calculations, wherein no allowance was(More)
We describe a new method for tonometry of small amounts of blood (up to 0.25 mL) at known pO2, PCO2, and temperature, in small, reusable, closed Pyrex flasks. Equilibrated blood is analyzed for oxygen saturation, pH, and organic phosphate concentration with standard techniques, and its p50 (the pO2 at which hemoglobin is half-saturated with oxygen) is(More)
We investigated the effect of temperature (19, 30, 37, and 43 degrees C) on the p50 value for normal human blood at pco2 = 5.72 kPa (43 mmHg), at various pHs (range 7.0 to 7.6) and molar ratios of [2,3-diphosphoglycerate]/[Hb4] (range 0.4 to 2.4). The d(log p50)/d(pH) coefficient varied from 0.39 at 19 degrees C to 0.35 at 43 degrees C. The relationship(More)
To investigate the mechanism of allosteric switching in human hemoglobin, we have studied the dissociation of the ligand (CO) from several intermediate ligation states by a stopped-flow kinetic technique that utilizes competitive binding of CO by microperoxidase. The hemoglobin species investigated include Hb(CO)4, the diliganded symmetrical species (alpha(More)
We report here the development of a new method that allows continuous determination of the oxygen dissociation curve for microsamples (600 mul) of whole blood under conditions of pH, pCO2, methemoglobin concentration, and 2,3-diphosphoglycerate content closely approaching those found in the circulatory system. The method consists of gradually oxygenating a(More)
We report the conditions (buffer composition and enzyme activity) required for estimating three frequently determined analytes--urea, glucose, and creatinine--by use of an improved version of the differential pH apparatus previously described (Clin Chem 29: 80-85, 1983). For each analyte, we used only one specific enzyme, thus avoiding a chain of auxiliary(More)
We analyzed 56 O2 equilibrium curves of fresh human blood, each from 0 to 150 Torr Po2. The data were collected over ranges of values for the 2,3-diphosphoglyceric acid-to-hemoglobin concentration ratio [DPG]/[Hb] of 0.2-2.7, for pH of 7.0-7.8, and for Pco2 of 7-70 Torr. Each curve was characterized according to the Adair scheme for the stepwise oxygenation(More)