Binding of human carbonic anhydrase to human hemoglobin.

The ability of human carbonic anhydrases to interact with human CO-hemoglobin have been studied with the counter-current distribution technique in aqueous/aqueous biphasic systems. The experimental results show that human carbonic anhydrase II interacts with human CO-hemoglobin whereas human carbonic anhydrase I does not. THe interaction between CO-hemoglobin and carbonic anhydrase II was quantified using the theoretical model developed previously for one-to-one interacting systems. [Backman, L. and Shanbhag, V.P. (1979) J. Chromatogr. 171, 1-13]. The apparent association constant was estimated to be 4.1 x 10(5) l mol-1 at pH 8.0 and 21 degrees C for the association of carbonic anhydrase II and CO-hemoglobin.