The affinities of the individual subunits in human adult and fetal hemoglobins to azide ion have been determined from the combined analysis of NMR and optical titration data. Structural and functional non-equivalence of the constituent subunits, i.e. K K and L L subunits in human adult hemoglobin and K K and Q Q subunits in human fetal hemoglobin, has been confirmed. The function of the K K subunits, which are common to both hemoglobins, is essentially identical in these hemoglobins and, in spite of the substitutions of 39 amino acid residues between L L and Q Q subunits, they exhibit similar azide ion affinities. The present study also demonstrates that the NMR spectral comparison between the two proteins provides signal assignments to the individual subunits in intact tetramer.z 1998 Federation of European Biochemical Societies.

-at the beginning of the experiment in December, it became apparent that 800 mg/plant of nitrate would be sufficient for radish growth in the cold season. In conclusion, we propose the QNM method supplying the whole amount of nutrients required for crop growth at the beginning of cultivation so that radish plants could be produced without draining nutrient solution containing a large amount of NO 3 -from the hydroponic system into the environment.