Abstract
A cyanide-degrading enzyme from Bacillus pumilus C1 has been purified and characterized. This enzyme consisted of three polypeptides of 45.6, 44.6, and 41.2 kDa; the molecular mass by gel filtration was 417 kDa. Electron microscopy revealed a multimeric, rod-shaped protein approximately 9 by 50 nm. Cyanide was rapidly degraded to formate and ammonia. Enzyme activity was optimal at 37 degrees C and pH 7.8 to 8.0. Activity was enhanced by Sc3+, Cr3+, Fe3+, and Tb3+; enhancement was independent of metal ion concentration at concentrations above 5 microM. Reversible enhancement of enzymatic activity by azide was maximal at 4.5 mM azide and increased with time. No activity was recorded with the cyanide substrate analogs CNO-, SCN-, CH3CN, and N3- and the possible degradation intermediate HCONH2. Kinetic studies indicated a Km of 2.56 +/- 0.48 mM for cyanide and a Vmax of 88.03 +/- 4.67 mmol of cyanide per min/mg/liter. The Km increased approximately twofold in the presence of 10 microM Cr3+ to 5.28 +/- 0.38 mM for cyanide, and the Vmax increased to 197.11 +/- 8.51 mmol of cyanide per min/mg/liter. We propose naming this enzyme cyanide dihydratase.
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- FAWCETT J. K., SCOTT J. E. A rapid and precise method for the determination of urea. J Clin Pathol. 1960 Mar;13:156–159. doi: 10.1136/jcp.13.2.156. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fry W. E., Millar R. L. Cyanide degradion by an enzyme from Stemphylium loti. Arch Biochem Biophys. 1972 Aug;151(2):468–474. doi: 10.1016/0003-9861(72)90523-1. [DOI] [PubMed] [Google Scholar]
- Harris R., Knowles C. J. Isolation and growth of a Pseudomonas species that utilizes cyanide as a source of nitrogen. J Gen Microbiol. 1983 Apr;129(4):1005–1011. doi: 10.1099/00221287-129-4-1005. [DOI] [PubMed] [Google Scholar]
- Ingvorsen K., Højer-Pedersen B., Godtfredsen S. E. Novel cyanide-hydrolyzing enzyme from Alcaligenes xylosoxidans subsp. denitrificans. Appl Environ Microbiol. 1991 Jun;57(6):1783–1789. doi: 10.1128/aem.57.6.1783-1789.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Knowles C. J., Bunch A. W. Microbial cyanide metabolism. Adv Microb Physiol. 1986;27:73–111. doi: 10.1016/s0065-2911(08)60304-5. [DOI] [PubMed] [Google Scholar]
- Knowles C. J. Microorganisms and cyanide. Bacteriol Rev. 1976 Sep;40(3):652–680. doi: 10.1128/br.40.3.652-680.1976. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kunz D. A., Nagappan O., Silva-Avalos J., Delong G. T. Utilization of cyanide as nitrogenous substrate by Pseudomonas fluorescens NCIMB 11764: evidence for multiple pathways of metabolic conversion. Appl Environ Microbiol. 1992 Jun;58(6):2022–2029. doi: 10.1128/aem.58.6.2022-2029.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
- Meyers P. R., Gokool P., Rawlings D. E., Woods D. R. An efficient cyanide-degrading Bacillus pumilus strain. J Gen Microbiol. 1991 Jun;137(6):1397–1400. doi: 10.1099/00221287-137-6-1397. [DOI] [PubMed] [Google Scholar]
- Skowronski B., Strobel G. A. Cyanide resistance and cyanide utilization by a strain of Bacillus pumilus. Can J Microbiol. 1969 Jan;15(1):93–98. doi: 10.1139/m69-014. [DOI] [PubMed] [Google Scholar]
- Wang P., Matthews D. E., VanEtten H. D. Purification and characterization of cyanide hydratase from the phytopathogenic fungus Gloeocercospora sorghi. Arch Biochem Biophys. 1992 Nov 1;298(2):569–575. doi: 10.1016/0003-9861(92)90451-2. [DOI] [PubMed] [Google Scholar]
- Wang P., VanEtten H. D. Cloning and properties of a cyanide hydratase gene from the phytopathogenic fungus Gloeocercospora sorghi. Biochem Biophys Res Commun. 1992 Sep 16;187(2):1048–1054. doi: 10.1016/0006-291x(92)91303-8. [DOI] [PubMed] [Google Scholar]