UP until now, all methods using NMR technique to study the coordinated structure of activecenter in metalloenzyme are to reconstitute the diamagnetic ions [i. e. Zn(Ⅱ), etc.] in metal-loenzyme or its paramagnetic ions [i. e. Cu(Ⅱ), etc] whose electronic relaxation times are notshort enough to substitute the metal ions of active center in enzyme with [Co(Ⅱ), Ni(Ⅱ)],which are paramagnetic and whose electronic relaxation time is shorter, so that the ~1H NMRspectra of the coordinated structure of active center are separated from those of the rest of en- UP until now, all methods using NMR technique to study the coordinated structure of active center in metalloenzyme are to reconstitute the diamagnetic ions [ie Zn (II), etc.] in metal-loenzyme or its paramagnetic ions [ie Cu (II) ] whose electronic relaxation times are not short enough to substitute the metal ions of active center in enzyme with [Co (II), Ni (II)], which are paramagnetic and whose electronic relaxation time is shorter, so that the ~ 1H NMR spectra of the coordinated structure of active center are separated from those of the rest of en-