ON THE ACTIVE-SITES OF HYDROGENASE FROM DESULFOVIBRIO-VULGARIS MIYAZAKI-F

An EXAFS study of hydrogenase solution has been carried out at Ni and Fe K- absorption edge. The presence of Ni atom was confirmed by the ob served jump at Ni K-edge, and the ratio of the content of Ni atom and Fe atom was estimated to be 1:15 based on the ratio of the K-edge jump magnitudes. The EXAFS data at Fe K-edge were analyzed by radial distr ibution function. Both plausible model of Fe4S4 and Fe3S4 clusters cou ld account for the oserved data. It is most probable that the active c enter of hydrogenase consists of Fe4S4 and Fe3S4 clusters and Ni atom is also included in an enzyme molecule.