ビタミンＢ１２酵素機能に学ぶ環境浄化触媒

Abstract

This account describes a current summary of our research on the development of bio-inspired catalysts with vitamin B12 enzyme functions for degradation of environmental pollutants. We have been interested in vitamin B12-dependent enzymes, involving the cobalt species as a catalytic center, and dealing with a hydrophobic vitamin B12, heptamethyl cobyrinate perchlorate, which has ester groups in place of the peripheral amide moieties of the naturally occurring vitamin B12. In order to construct a good catalytic system, we prepared various nanomaterials with vitamin B12 activities. For example, a vesicle-type artificial enzyme composed of peptide lipids and hydrophobic vitamin B12, a vitamin B12-ruthenium photo-sensitizer system, a vitamin B12-titanium dioxide hybrid catalyst and so on. These bio-inspired catalysts are very interesting from the viewpoint of green chemistry. 1,1-bis(4-chlorophenyl)- 2,2,2-trichloroethane (DDT) is characterized by a pronounced insecticidal property and has been used worldwide for the last several decades despite its known hazardous effects on human health and wildlife. Because of recent environmental concerns, there is pressing need for efficient methods for degradation of such chlorinated compounds accumulated in the soil. DDT was degradated effectively by the electrochemical method and the bio-inspired catalysts with vitamin B12 function. Such vitamin B12 derivatives also can apply the detoxification of inorganic arsenic by the methylation.