Characterization of the new [beta]-glucuronidase from Streptococcus equi subsp. zooepidemicus

• Published in: Applied microbiology and biotechnology 2007-04, Vol.74 (5), p.1016
• Main Authors: Krahulec, Ján, Krahulcová, Jana
• Format: Article
• Language: English
• Subjects: Bacteria; Bacteriology; E coli; Enzymatic activity; Enzymes
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-006-0745-3

Recently, a new gene encoding β-glucuronidase from Streptococcus equi subsp. zooepidemicus (SEZ) was identified and expressed in Escherichia coli. In this paper, the characterization of the enzyme is described. Specific enzyme activity was 120,000 U/mg purified protein at 37°C and pH=7.0. The temperature and pH value, at which the enzyme has the highest specific activity, were determined and were found to be approximately 52°C and 5.6, respectively. The mutant strain SEZ glcHis was designed for the efficient isolation of β-glucuronidase from S. equi subsp. zooepidemicus. It was observed that the specific activity of β-glucuronidase in the cytoplasmic extract of a mutated strain was about 45% lower than in the cytoplasmic extract of a wild-type strain. The specific activity of purified β-glucuronidase from SEZ glcHis was four times as low as β-glucuronidase purified from E. coli. Comparing the specific activity of purified streptococcal β-glucuronidase from E. coli with E. coli β-glucuronidase (the enzyme with the highest specific activity was supplied by Sigma), the former is 1.8 higher than the latter.[PUBLICATION ABSTRACT]