Localization, purification and properties of a tetrathionate hydrolase from Acidithiobacillus caldus

The moderately thermophilic bacterium Acidithiobacillus caldus is found in bacterial populations in many bioleaching operations throughout the world. This bacterium oxidizes elemental sulfur and other reduced inorganic sulfur compounds as the sole source of energy. The purpose of this study was to p...

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Bibliographic Details
Published inEuropean journal of biochemistry Vol. 271; no. 2; pp. 272 - 280
Main Authors Bugaytsova, Zhanna, Lindström, E. Börje
Format Journal Article
LanguageEnglish
Published Oxford, UK Blackwell Science Ltd 01.01.2004
Subjects
Acidithiobacillus - enzymology
Acidithiobacillus caldus
Chromatography, High Pressure Liquid
Hydrogen-Ion Concentration
Hydrolases - chemistry
Hydrolases - isolation & purification
Hydrolases - metabolism
intracellular protein localization
Isoelectric Point
protein purification
reduced inorganic sulfur compounds
Subcellular Fractions
Substrate Specificity
tetrathionate hydrolase
Tetrathionic Acid - metabolism
Thiosulfates - metabolism
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Summary:The moderately thermophilic bacterium Acidithiobacillus caldus is found in bacterial populations in many bioleaching operations throughout the world. This bacterium oxidizes elemental sulfur and other reduced inorganic sulfur compounds as the sole source of energy. The purpose of this study was to purify and characterize the tetrathionate hydrolase of A. caldus. The enzyme was purified 16.7‐fold by one step chromatography using a SP Sepharose column. The purified enzyme resolved into a single band in 10% polyacrylamide gel, both under denaturing and native conditions. Its homogeneity was confirmed by N‐terminal amino acid sequencing. Tetrathionate hydrolase was shown to be a homodimer with a molecular mass of 103 kDa (composed from two 52 kDa monomers). The purified enzyme had optimum activity at pH 3.0 and 40 °C and an isoelectric point of 9.8. The periplasmic localization of the enzyme was determined by differential fractionation of A. caldus cells. Detected products of the tetrathionate hydrolase reaction were thiosulfate and pentathionate as confirmed by RP‐HPLC analysis. The activity of the purified enzyme was drastically enhanced by divalent metal ions.
Bibliography:Department of Odontology, Umeå University, S‐90187 Umeå, Sweden.
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ISSN:0014-2956
1432-1033
1432-1033
DOI:10.1046/j.1432-1033.2003.03926.x