A thiocyanate hydrolase of Thiobacillus thioparus. A novel enzyme catalyzing the formation of carbonyl sulfide from thiocyanate

• Published in: The Journal of biological chemistry Vol. 267; no. 13; pp. 9170 - 9175
• Main Authors: KATAYAMA, Y, NARAHARA, Y, INOUE, Y, AMANO, F, KANAGAWA, T, KURAISHI, H
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 05-05-1992
• Subjects: Analytical, structural and metabolic biochemistry; ANTITHYROID DRUGS; BACTERIA; Biological and medical sciences; BIOSYNTHESIS; Blotting, Western; CARBONIC ACID DERIVATIVES; CATALYSIS; CHALCOGENIDES; characterization; CHROMATOGRAPHY; Chromatography, Liquid; DRUGS; ELECTROPHORESIS; Electrophoresis, Polyacrylamide Gel; ENZYME ACTIVITY; ENZYMES; Enzymes and enzyme inhibitors; Fundamental and applied biological sciences. Psychology; HORMONE ANTAGONISTS; HYDROLASES; Hydrolases - isolation & purification; Hydrolases - metabolism; Hydrolysis; Immunochemistry; Kinetics; LIQUID COLUMN CHROMATOGRAPHY; METABOLISM; MICROORGANISMS; MOLECULAR WEIGHT; ORGANIC COMPOUNDS; ORGANIC SULFUR COMPOUNDS; PROTEINS; purification; RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT; SEPARATION PROCESSES; SULFIDES; SULFUR COMPOUNDS; Sulfur Oxides - metabolism; SYNTHESIS 560300 > Chemicals Metabolism & Toxicology; Thiobacillus - enzymology; Thiobacillus thioparus; thiocyanate hydrolase; THIOCYANATES; Thiocyanates - metabolism; Thiobacillus thioparus; Purification; Enzymatic activity; Enzyme; Immunoblotting assay; Bacteria; Kinetics; Ion exchange chromatography
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/s0021-9258(19)50404-5

A thiocyanate hydrolase that catalyzes the first step in thiocyanate degradation was purified to homogeneity from Thiobacillus
thioparus, an obligate chemolithotrophic eubacterium metabolizing thiocyanate to sulfate as an energy source. The thiocyanate
hydrolase was purified 52-fold by steps involving ammonium sulfate precipitation, DEAE-Sephacel column chromatography, and
hydroxylapatite column chromatography. The enzyme hydrolyzed 1 mol of thiocyanate to form 1 mol of carbonyl sulfide and 1
mol of ammonia as follows: SCN- + 2H2O---COS + NH3 + OH-. This is the first report describing the hydrolysis of thiocyanate
to carbonyl sulfide by an enzyme. The enzyme had a molecular mass of 126 kDa and was composed of three different subunits:
alpha (19 kDa), beta (23 kDa), and gamma (32 kDa). The enzyme exhibited optimal activities at pH 7.5-8.0 and at temperatures
ranging from 30 to 40 degrees C. The Km value for thiocyanate was approximately 11 mM. Immunoblot analysis with polyclonal
antibodies against the purified enzyme suggested that it was induced in T. thioparus cells when the cells were grown with
thiocyanate.