Archives of Microbiology

, Volume 138, Issue 1, pp 72–78

Purification and characterization of an inducible dissimilatory type sulfite reductase from Clostridium pasteurianum

  • Gail Harrison
  • Carol Curle
  • Edward J. Laishley
Original Papers

DOI: 10.1007/BF00425411

Cite this article as:
Harrison, G., Curle, C. & Laishley, E.J. Arch. Microbiol. (1984) 138: 72. doi:10.1007/BF00425411

Abstract

An inducible sulfite reductase was purified from Clostridium pasteurianum. The pH optimum of the enzyme is 7.5 in phosphate buffer. The molecular weight of the reductase was determined to be 83,600 from sodium dodecyl sulfate gel electrophoresis with a proposed molecular structure: α2β2. Its absorption spectrum showed a maximum at 275 nm, a broad shoulder at 370 nm and a very small absorption maximum at 585 nm. No siroheme chromophore was isolated from this reductase. The enzyme could reduced the following substrates in preferential order: NH2OH> SeO32->NO22-at rates 50% or less of its preferred substrate SO32-. The proposed dissimilatory intermediates, S3O62-or S2O32-, were not utilized by this reductase while KCN inhibited its activity. Varying the substrate concentration [SO32-] from 1 to 2.5 μmol affected the stoichiometry of the enzyme reaction by alteration of the ratio of H2 uptake to S2- formed from 2.5:1 to 3.1:1. The inducible sulfite reductase was found to be linked to ferredoxin which could be completely replaced by methyl viologen or partially by benzyl viologen. Some of the above-mentioned enzyme properties and physiological considerations indicated that it was a dissimilatory type sulfite reductase.

Key words

Clostridium posteurianumSulfite reductaseSulfite metabolism

Abbreviations

SDS

sodium dodecyl sulfate

BSA

bovine serum albumin

LDH

Lactate dehydrogenase

Copyright information

© Springer-Verlag 1984

Authors and Affiliations

  • Gail Harrison
    • 1
  • Carol Curle
    • 1
  • Edward J. Laishley
    • 1
  1. 1.Department of BiologyThe University of CalgaryCalgaryCanada