Characterization of anaerobic sulfite reduction by Salmonella typhimurium and purification of the anaerobically induced sulfite reductase
- Universite de Montreal, Quebec (Canada)
- Univ. of California, Davis (USA)
Mutants of Salmonella typhimurium that lack the biosynthetic sulfite reductase (cysI and cysJ mutants) retain the ability to reduce sulfite for growth under anaerobic conditions. Here we report studies of sulfite reduction by a cysI mutant of S. typhimurium and purification of the associated anaerobic sulfite reductase. Sulfite reduction for anaerobic growth did not require a reducing atmosphere but was prevented by an argon atmosphere contaminated with air (<0.33%). It was also prevented by the presence of 0.1 mM nitrate. Anaerobic growth in liquid minimal medium, but not on agar, was found to require additions of trace amounts (10{sup {minus}7} M) of cysteine. Spontaneous mutants that grew under the argon contaminated with air also lost the requirement for 10{sup {minus}7}M cysteine for anaerobic growth in liquid. A role for sulfite reduction in anaerobic energy generation was contraindicated by the findings that sulfite reduction did not improve cell yields, and anaerobic sulfite reductase activity was greatest during the stationary phase of growth. Sulfite reductase was purified from the cytoplasmic fraction of the anaerobically grown cysI mutant and was purified 190-fold. The most effective donor in crude extracts was NADH. NADHP and methyl viologen were, respectively, 40 and 30% as effective as NADH. Oxygen reversibly inhibited the enzyme. The anaerobic sulfite reductase showed some resemblance to the biosynthetic sulfite reductase, but apparently it has a unique, as yet unidentified function.
- OSTI ID:
- 6945871
- Journal Information:
- Journal of Bacteriology; (USA), Vol. 171:6; ISSN 0021-9193
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SALMONELLA TYPHIMURIUM
ENZYME ACTIVITY
SULFITES
REDUCTION
ANAEROBIC CONDITIONS
INHIBITION
MUTANTS
OXIDOREDUCTASES
OXYGEN
PURIFICATION
BACTERIA
CHEMICAL REACTIONS
ELEMENTS
ENZYMES
MICROORGANISMS
NONMETALS
OXYGEN COMPOUNDS
SALMONELLA
SULFUR COMPOUNDS
550200* - Biochemistry