Glutathione Reductase in Wheat Grain. 1. Isolation and Characterization

• Published in: Journal of agricultural and food chemistry 2000-10, Vol.48 (10), p.4978-4983
• Main Authors: de Lamotte, Frédéric, Vianey-Liaud, Nicolas, Duviau, Marie-Pierre, Kobrehel, Károly
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Blotting, Western; Economic plant physiology; Electrophoresis, Polyacrylamide Gel; Enzymes; Food engineering; Fundamental and applied biological sciences. Psychology; Glutathione Reductase - chemistry; Glutathione Reductase - isolation & purification; Hydrogen-Ion Concentration; Life Sciences; Metabolism; Molecular Weight; Nutrition. Photosynthesis. Respiration. Metabolism; Plant physiology and development; Plant Proteins - chemistry; Plant Proteins - isolation & purification; Triticum - enzymology
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf0003808

Durum wheat (Triticum durum, Desf.) endosperm of mature kernels contained a single form of glutathione reductase (GR); it appeared about the 18th day after anthesis while another isoform, present at the early stages of grain development, disappeared between the 20th and 30th days after flowering. The form that was present at grain maturity was isolated and characterized. It was composed of two monomers, each one having an apparent molecular mass of about 60 kDa. The K m values for NADPH and for GSSG were 3.7 and 9.1 μM, respectively, and the V m values for NADPH and for GSSG were 594 and 575 μkat·mg-1 protein, respectively. The pHi of the enzyme was situated between pH 4.4 and 4.5. At a constant temperature of 25 °C, the optimum GR activity was found to be between pH 7.5 and 8.0. It was relatively resistant to high temperatures and was very resistant to very low temperatures. Keywords: Glutathione reductase; wheat; glutathione; enzyme; proteins