The role of sulfoacetaldehyde sulfo-lyase in the mineralization of isethionate by an environmental Acinetobacter isolate

1 School of Biology, The Queen's University of Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, Northern Ireland 2 Biochemistry and School of Chemistry, The Queen's University of Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, Northern Ireland *Author for correspondence: John P. Quinn. Tel: + 44 1232 272287. Fax: +44 1232 236.505. e-mail: j.quinn@qub.ac.uk ABSTRACT Summary: An environmental Acinetobacter isolate, strain ICD, utilized isethionate at concentrations up to at least 20 mM as carbon and energy source, with essentially quantitative sulfate accumulation. The initial step in isethionate metabolism is likely to be its oxidation to sulfoacetaldehyde since inducible sulfoacetaldehyde sulfo-lyase activity was demonstrated in isethionate-grown cells by in vitro assay and gel zymography; sulfoacetaldehyde itself did not induce the enzyme. Isethionate-grown cells of Acinetobacter sp. ICD, unlike those of most other C-S bond-cleaving strains described, also contained an inducible sulfite-oxidizing activity. The results provide further evidence that sulfoacetaldehyde sulfo-lyase plays a central role in the mineralization of biogenic sulfonates. Keywords: isethionate, sulfoacetaldehyde sulfo-lyase, sulfite oxidase, sulfonate, Acinetobacter sp. Present address: Randox Laboratories Ltd, Crumlin BT29 4QY, Northern Ireland.