A Mu-class glutathione S-transferase from gills of the marine shrimp Litopenaeus vannamei: Purification and characterization

Glutathione S‐transferases (GSTs) are a family of detoxifying enzymes that catalyze the conjugation of glutathione (GSH) to electrophiles, thereby increasing the solubility of GSH and aiding its excretion from the cell. In this study, a glutatione S‐transferase from the gills of the marine shrimp Li...

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Bibliographic Details
Published in:Journal of biochemical and molecular toxicology 2007-04, Vol.21 (2), p.62-67
Main Authors: Contreras-Vergara, Carmen A., Valenzuela-Soto, Elisa, García-Orozco, Karina D., Sotelo-Mundo, Rogerio R., Yepiz-Plascencia, Gloria
Format: Article
Language:English
Subjects:
Animals
Chromatography, Affinity
Electrophoresis, Polyacrylamide Gel
Gills
Gills - enzymology
Glutathione S-Transferase
Glutathione Transferase - chemistry
Glutathione Transferase - isolation & purification
Kinetic Characterization
Litopenaeus vannamei
Marine
Penaeidae - enzymology
Purification
Shrimp
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Summary:Glutathione S‐transferases (GSTs) are a family of detoxifying enzymes that catalyze the conjugation of glutathione (GSH) to electrophiles, thereby increasing the solubility of GSH and aiding its excretion from the cell. In this study, a glutatione S‐transferase from the gills of the marine shrimp Litopenaeus vannamei was purified by affinity chromatography using a glutathione–agarose affinity column. GST was purified to homogeneity as judged by reducing SDS‐PAGE and zymograms. This enzyme is a homodimer composed of ∼25‐kDa subunits and identified as a Mu‐class GST based on its activity against 1‐chloro‐2,4‐dinitrobenzene (CDNB) and internal peptide sequence. The specific activity of purified GST was 440.12 μmol/(min mg), and the Km values for CDNB and GSH are very similar (390 and 335 μM, respectively). The intersecting pattern of the initial velocities of this enzyme in the Lineweaver–Burke plot is consistent with a sequential steady‐state kinetic mechanism. The high specific activity of shrimp GST may be related to a highly effective detoxification mechanism necessary in gills since they are exposed to the external and frequently contaminated environment. © 2007 Wiley Periodicals, Inc. J Biochem Mol Toxicol 21:62–67, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20162
ISSN:1095-6670
1099-0461
DOI:10.1002/jbt.20162