Existence of a new type of sulfite oxidase which utilizes ferric ions as an electron acceptor in Thiobacillus ferrooxidans

Journal Article · Fri Jan 01 00:00:00 EST 1988 · Appl. Environ. Microbiol.; (United States)

OSTI ID:5272565

Sugio, T; Katagiri, T; Moriyama, M; Zhen, Y L; Inagaki, K; Tano, T

A new type of sulfite oxidase which utilizes ferric ion (Fe/sup 3 +/) as an electron acceptor was found in iron-grown Thiobacillus ferrooxidans. It was localized in the plasma membrane of the bacterium and had a pH optimum at 6.0. Under aerobic conditions, 1 mol of sulfite was oxidized by the enzyme to produce 1 mol of sulfate. Under anaerobic conditions in the presence of Fe/sup 3 +/, sulfite was oxidized by the enzyme as rapidly as it was under aerobic conditions. In the presence of o-phenanthroline or a chelator for Fe/sup 2 +/, the production of Fe/sup 2 +/ was observed during sulfite oxidation by this enzyme under not only anaerobic conditions but also aerobic conditions. No Fe/sup 2 +/ production was observed in the absence of o-phenanthroline, suggesting that the Fe/sup 2 +/ produced was rapidly reoxidized by molecular oxygen. Neither cytochrome c nor ferricyanide, both of which are electron acceptors for other sulfite oxidases, served as an electron acceptor for the sulfite oxidase of T. ferrooxidans. The enzyme was strongly inhibited by chelating agents for Fe/sup 3 +/. The physiological role of sulfite oxidase in sulfur oxidation of T. ferrooxidans is discussed.

• Research Organization: Okayama Univ., Japan
• OSTI ID: 5272565
• Journal Information: Appl. Environ. Microbiol.; (United States), Vol. 54:1
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
01 COAL, LIGNITE, AND PEAT
SULFITES
OXIDATION
THIOBACILLUS FERROXIDANS
ENZYME ACTIVITY
AEROBIC CONDITIONS
ANAEROBIC CONDITIONS
IRON COMPOUNDS
BACILLUS
BACTERIA
CHEMICAL REACTIONS
MICROORGANISMS
OXYGEN COMPOUNDS
SULFUR COMPOUNDS
SULFUR-OXIDIZING BACTERIA
TRANSITION ELEMENT COMPOUNDS
550200* - Biochemistry
550700 - Microbiology
010300 - Coal
Lignite
& Peat- Preparation- (1987-)