Aubailly M, Haigle J, Giordani A, Morlière P, Santus R. UV photolysis of catalase revisited: a spectral study of photolytic intermediates.
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2000;
56:61-7. [PMID:
11073317 DOI:
10.1016/s1011-1344(00)00061-0]
[Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The 365-nm irradiation of 4.6 microM (approximately equal to 1.1 mg/ml) catalase solutions in pH 7.4 phosphate buffer induces spectral modifications. Difference spectra show maxima at 434, 555, 584 nm at the beginning of the irradiation, then a final spectrum with a maximum at 568 nm and a shoulder at 530 nm is observed. These results suggest the formation of compound III (oxyferrous catalase) and compound II, respectively. In deaerated 0.1 M, pH 8.7 borate buffer, the ferrous catalase is characterized by maxima at 563 and 594 nm. Hydrogen donors such as ethyl alcohol, formate and p-cresol inhibit, but citrate ions enhance the formation of these intermediates. A mechanism involving Fe(III) reduction according to an internal electron transfer is proposed.
Collapse