Kinetics of CO2 exchange in human erythrocytes analyzed by 13C-NMR

The 13C-nuclear magnetic resonance signals of CO2 and bicarbonate have been studied in suspensions of mature human erythrocytes, in lysed suspensions, and in supernatant solutions. This technique requires no chemical perturbation of the samples analyzed. When care is taken to avoid technical artifacts, lysis produces only a slight broadening of the 13CO2 spectral line. The results are consistent with the concept that CO2 exchange is primarily determined by the kinetics of intracellular carbonic anhydrase and not by the permeability of the erythrocyte membrane.