UV-B induced changes in antioxidant enzymes and their isoforms in cucumber (Cucumis sativus L.) cotyledons.
To assess the role of antioxidant defense system on exposure to ultra-violet-B (UV-B) radiation, the activities of antioxidant enzymes superoxide dismutase (SOD), ascorbic acid peroxidase (APX), glutathione reductase (GR) and guaiacol peroxidase (GPX), as well as the level of antioxidants ascorbic acid (AA) and alpha-tocopherol were monitored in cucumber (Cucumis sativus L. var long green) cotyledons. UV-B enhanced the activity of antioxidant enzymes as well as AA content, but decreased the level of alpha-tocopherol. Significant increase was observed in the activities of SOD and GPX. Analysis of isoforms of antioxidant enzymes by native-PAGE and activity staining revealed three isoforms of GPX in unexposed dark-grown cotyledons (control), and their intensity was enhanced by UV-B exposure. In addition, four new isoforms of GPX were observed in cotyledons after UV-B exposure. Although no new isoforms were observed for the other antioxidant enzymes, the activities of their existing isoforms were enhanced by UV-B.
Kataria
Sunita
S
School of Life Sciences, Vigyan Bhawan, Khandwa Road Campus, D.A. University, Indore, India. sunitakataria@hotmail.com
Jain
Karishma
K
Guruprasad
K N
KN
D000975:Antioxidants / Q000378:metabolism*; D060387:Ascorbate Peroxidases; D018548:Cotyledon / Q000201:enzymology / Q000528:radiation effects; D018553:Cucumis sativus / Q000201:enzymology* / Q000528:radiation effects*; D005980:Glutathione Reductase / Q000378:metabolism / Q000528:radiation effects; D007527:Isoenzymes / Q000378:metabolism / Q000528:radiation effects; D009195:Peroxidase / Q000378:metabolism / Q000528:radiation effects; D010544:Peroxidases / Q000378:metabolism / Q000528:radiation effects; D013482:Superoxide Dismutase / Q000378:metabolism / Q000528:radiation effects; D014466:Ultraviolet Rays
D000975:Antioxidants; D007527:Isoenzymes; D010544:Peroxidases; C121048:guaiacol peroxidase; D060387:Ascorbate Peroxidases; D009195:Peroxidase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase