Purification, characterization and in vitro application of a thermostable oxidant- and @entity214 -stable XXXX from a newly isolated Bacillus firmus DWD-33.

@entity10694 @entity1 @entity1568 @entity274 @entity1025 @entity7969 @entity71664 @entity33345 @entity7437 @entity920 @entity1460 @entity505 @entity1098 @entity214 @entity414
UNASSIGNED: A thermostable oxidant- and @entity214 -stable @entity33345 was produced from a newly isolated B. firmus DWD-33. Maximum enzyme productivity was obtained in medium containing 0.8% @entity7969 and 1.2% @entity1460 powder as @entity505 and @entity1568 sources, respectively. Enzyme purification increased the specific activity to 24-fold with 27% recovery and molecular weight of 33.5 kDa. As compared with other microbial uricases, the pure enzyme showed high thermostability and other unique characters. The Vmax was 387   M/min, the turnover number (Kcat) was 21.8*103 s-1 and the catalytic efficiency (Kcat /Km) was 2.76*108 s-1M-1. The enzyme was stable at pH 7.0-10.0 and up to 70   C. The optimal reaction temperature and pH of enzyme were 50   C and pH 8.0, respectively. @entity1025 significantly enhanced the enzymatic activity, while @entity10694 , @entity1098 and @entity7437 greatly suppressed the activity. @entity1025 might be the @entity33345 cofactor as the enzyme activity was restored after its addition to @entity1098 -chelated enzyme. The enzyme inhibition by the @entity920 -chelating agent @entity71664 suggests that this enzyme is a cuprouricase-type. The purified @entity33345 retained 72 and 82% of its original activity even after incubation with 0.5% @entity274 and 0.5% @entity214 for 6 h, respectively. The application of enzyme in the in vitro measurement of @entity414 in @entity1 sera was promising and none of @entity414 analogs was a competitive substrate for enzyme, indicative of the high specificity of @entity33345 with respect to @entity414 measurement in vitro. The reaction can be applied in clinical laboratory for 10 min only due to the absorbances are lineary related to @entity414 concentration up to 500   M.
