METHODS FOR PURIFICATION OF GLUTATHIONE-PEROXIDASE AND RELATED ENZYMES

The different preparative techniques and related analytical methods us ed for purification of glutathione peroxidase, glutathione transferase and glutathione reductase, described in papers published in the last ten years, have been reviewed in this article. Among the different pur ification techniques, chromatography has played a relevant role, being reported in all the papers reviewed, whereas other preparative techni ques such as electrophoresis and isoelectric focusing were less employ ed and have been reported in only ca. 3% of cases. Frequently, several different chromatographic modes and several rechromatography steps ha ve been employed. The use of at least three different chromatographic modes has been reported in 53% of total reviewed papers, whereas 41% o f them employed two differents modes and in only 6% a single preparati ve chromatographic step was used. To evaluate losses and improve recov ery, analytical methods for quantitation of protein and assay of enzym atic activity must be used in each purification step. Among these anal ytical techniques, gel electrophoresis, under denaturing conditions, h as been widely used to assess purity of enzyme preparation. A discussi on of the different activity assay methods used for these three enzyme s is also presented in this article.