Studies on the function of abnormal hemoglobins I. An improved method for automatic measurement of the oxygen equilibrium curve of hemoglobin

Abstract

An apparatus with which the continuous oxygen equilibrium curve of hemo globin can be recorded automatically was constructed and its performance was examined. The oxygen pressure in the hemoglobin solution and the degree of saturation of the hemoglobin with oxygen are determined by means of a Clark's oxygen electrode and by spectrophotometry, respectively. The deoxygenation of oxyhemoglobin is attained by introducing nitrogen gas into the reaction cell after about 90 min and the reoxygenation of deoxyhemoglobin by introducing air. The deoxygenation curve coincided well with the successive oxygenation curve of the same sample. The curves measured using monochromatic lights of various wavelengths in the visible range coincided well with each other, in so far as the measurements were done under the same conditions. This method is applicable to hemoglobin solutions of concentrations of 0.01–2%. The curve is reproduced very well if the experiments are carried out under the same conditions and within several days. This reproducibility, however, becomes worse when the experiments are carried out over a longer period. The standard error of the fractional saturation for the curves which have been measured over the past one year depends on the position on the curve and is a maximum, about 2%, near the point of half saturation. This apparatus can furnish us with easy, speedy and accurate means to measure the oxygen equilibrium curve and can facilitate the observation of fine structures of the curve. This method is suitable for studies on the function of abnormal hemoglobins.