Microplate quantification of enzymes of the plant ascorbate-glutathione cycle

Anal Biochem. 2008 Dec 15;383(2):320-2. doi: 10.1016/j.ab.2008.07.020. Epub 2008 Jul 26.


Here, we describe microplate assays for determining the specific activities of four enzymes that constitute the ascorbate-glutathione cycle: APX, MDHAR, DHAR, and GR. In plants, these enzymes play a major role in detoxifying reactive oxygen species produced in cells under environmental stress. This work presents the development of plate reader assays to allow rapid analysis of the ascorbate-glutathione cycle activity using tomato fruits subjected to salt stress as a model. With this method, it is possible to analyze easily in one day the activities of the four enzymes for 30 experimental samples, all in triplicate and with blanks.

MeSH terms

  • Ascorbate Peroxidases
  • Ascorbic Acid / metabolism*
  • Fruit / enzymology
  • Glutathione / metabolism*
  • Glutathione Reductase / metabolism
  • Lycopersicon esculentum / enzymology*
  • NADH, NADPH Oxidoreductases / metabolism
  • Oxidoreductases / metabolism
  • Peroxidases / metabolism


  • Oxidoreductases
  • Peroxidases
  • Ascorbate Peroxidases
  • NADH, NADPH Oxidoreductases
  • monodehydroascorbate reductase (NADH)
  • Glutathione Reductase
  • glutathione dehydrogenase (ascorbate)
  • Glutathione
  • Ascorbic Acid