STRUCTURAL-ANALYSIS OF COMPOUND-I IN HEMOPROTEINS - STUDY ON PROTEUS-MIRABILIS CATALASE

Ferryl catalysis has attracted considerable interest, because a divers e variety of enzymes use ferryl intermediates to perform difficult che mistry. The structure of the reactional intermediate compound I of Pro teus mirabilis catalase (PMC) has been solved using time-resolved X-ra y diffraction techniques and single crystal microspectrophotometry. Fo rmation of compound I is characterized by significant changes in the a bsorbance spectrum, and the creation of an oxoferryl group on the dist al side of the heme. This group is deafly visible in the X-ray electro n density maps. An unidentified electron density, likely to be an anio n because of the nature of its environment, appears during the reactio n, in a site distant from the heme. The structure of compound I in PMC is compared with that of compound I in cytochrome c peroxidase (CCP).