RESUMO
Recombinant 3-(5-oxo-2-thioxoimidazolidin-4-yl) propionic acid desulfhydrase (ErtC) derived from Burkholderia sp. HME13 was purified to homogeneity. Here, ErtC's kinetic parameters, optimum reaction temperature and pH, and stability at varying temperatures and pH and the effects of various additives on ErtC activity were determined. Real-time polymerase chain reaction and enzyme assays suggested that ergothioneine induced the expression of ertC.
Assuntos
Burkholderia , Ergotioneína , Propionatos , TemperaturaRESUMO
In our previous study, ertABC genes encoding ergothionase, thiourocanate hydratase, and 3-(5-oxo-2-thioxoimidazolidin-4-yl) propionic acid desulfhydrase were identified, all of which may be involved in ergothioneine utilization of Burkholderia sp. HME13. In this study, we identify the ertD gene encoding metal-dependent hydantoin-5-propionic acid amidohydrolase in this strain. Mn2+-containing ErtD showed maximum activity at 45 °C and pH 8.5 and was stable at temperatures up to 45 °C. The Km and Vmax values of Mn2+-containing ErtD for hydantoin-5-propionic acid were 2.8 m m and 16 U/mg, respectively. Real-time polymerase chain reaction (PCR) revealed that ertD expression levels in Burkholderia sp. HME13 cells cultivated in ergothioneine medium were 3.3-fold higher than those in cells cultivated in Luria-Bertani (LB) medium. ErtD activity in the crude extract from Burkholderia sp. HME13 cells cultured in ergothioneine medium was 0.018 U/mg, whereas that in LB medium was not detected. Accordingly, we suggest that ErtD is involved in ergothioneine utilization in this strain.
