RESUMO
Cholesterol oxidase is a highly demanded enzyme used in medicine, pharmacy, agriculture, chemistry, and biotechnology. It catalyzes oxidation of 3ß-hydroxy-5-ene- to 3-keto-4-ene- steroids with the formation of hydrogen peroxide. Here, we expressed 6xHis-tagged mature form of the extracellular cholesterol oxidase (ChO) from the actinobacterium Nocardioides simplex VKM Ac-2033D (55.6 kDa) in Escherichia coli cells. The recombinant enzyme (ChONs) was purified using affinity chromatography. ChONs proved to be functional towards cholesterol, cholestanol, phytosterol, pregnenolone, and dehydroepiandrosterone. Its activity depended on the structure and length of the aliphatic side chain at C17 atom of the steroid nucleus and was lower with pregnenolone and dehydroepiandrosterone. The enzyme was active in a pH range of 5.25÷6.5 with the pH optimum at 6.0. Kinetic assays and storage stability tests demonstrated that the characteristics of ChONs were generally comparable with or superior to those of commercial ChO from Streptomyces hygroscopicus (ChOSh). The results contribute to the knowledge on microbial ChOs and evidence that ChO from N. simplex VKM Ac-2033D is a promising agent for further applications.
Assuntos
Colesterol Oxidase , Fitosteróis , Actinobacteria , Colestanóis , Colesterol Oxidase/química , Desidroepiandrosterona/química , Peróxido de Hidrogênio , Pregnenolona , Esteroides/químicaRESUMO
The genome of an Achromobacter insolitus strain isolated from an agricultural soil polluted with the herbicide glyphosate is reported. The genome size is 6.4 Mb, with an average G+C content of 65.2%. These genomic data could contribute to a better understanding of the biochemistry and regulatory mechanisms of the microbial degradation of glyphosate and aminomethylphosphonate.
