The diffusion coefficient of human hemoglobin at high concentrations

The diffusion coefficient of human hemoglobin in 35 g/100 ml stromata-free solution has been measured and found to be 3.4× 10 −8 cm 2/sec at 25 °C. The measurement was made by noting the rate at which hemoglobin diffused from a sintered glass disc into a colorless protein solution of the same molecular weight and concentration as the hemoglobin. The protein was bovine serum albumin. Diffusion coefficients of hemoglobin were also measured in solutions ranging from 4.9 to 31.4 g/100 ml. The data are in semiquantitative agreement with those of previous investigators on rabbit and cow hemoglobin and at intermediate concentrations. The diffusion coefficient in 35 g/100 ml solution is in excellent agreement with that calculated from facilitated oxygen transport data on a red blood cell paste.