Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1926072 | Archives of Biochemistry and Biophysics | 2010 | 6 Pages |
Abstract
The imidase from Pseudomonas putida YZ-26 consisting of 293-amino acid residues is a novel imidase with four subunits as the holo-enzyme and low molecular weight which is significantly different from known mammalian imidase. This study measured the zinc-binding properties of the imidase using inductively coupled plasma-atomic emission spectrometry and competition assay combined with activity determinations. Results show that each subunit of the imidase binds the zinc ion by 1:1 stoichiometry with apparent binding constant of 9.5 Ã 108 Mâ1. The activity of the apo-imidase (20 μM) was recovered with the addition of zinc in the lower concentration (0-20 μM), whereas the enzymatic activity is decreased in the presence of high concentration of zinc (above 100 μM). The site-directed mutagenesis of His247, His86 or Cys7, Cys108 in imidase resulted in loss of activity and zinc-binding abilities at different degrees, showing that these residues may critically affect both enzymatic activity and conformation.
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Authors
Ya-Wei Shi, Xiao-Qin Liu, Peng Shi, Xue-Yao Zhang,