Biopolymers and cell. 2010; 26 (3): 218 - 224
Effect of 24-epibrassinolide on lipoxygenase activity in maize seedlings under cold stress
V. N. Kopich, S. V. Kretynin, O. V. Kharchenko, R. P. Litvinovskaya1, N. M. Chashina1, V. A. Khripach1
Institute of Bioorganic Chemistry and Petrochemistry of NAS of Ukraine, 1, Murmanska Str., Kyiv, Ukraine, 02160
1Institute of Bioorganic Chemistry of the NAS of Belarus, 5/2, Kuprevich str., Minsk, Belarus, 220141
Aim. To investigate 24-epibrassinolide influence on the maize seedlings 9- and 13-lipoxygenases activity (9- and 13-LOX) under normal conditions (25o C) and cold stress (5o C). Methods. LOX activity was measured after treatment of seedlings with 0.01 and 1 ìM 24-epibrassinolide. The enzymes were extracted from maize seedlings with 0.1 M sodium acetate (pH 4.5) buffer, supplemented with a non-ionic detergent (0.1 % Brij-99) and EDTA (0.1 mM). The 9- and 13-LOX activities were determined spectrophotometrically at 234 nm using linoleic acid as substrate at pH 6.0 and 7.0 in the presence or absence of 0.02 % Lubrol PX. Results. 3-6-fold increase in LOX activity of 24-epibrassinolide-treated seedlings was demonstrated under normal conditions. Cold stress in the presence of 1µM 24-epibrassinolide enhances the activities of 9- and 13-LOX by 4 and 10 times, respectively. Conclusions. The results obtained enlarge our understanding of possible pathways of LOX metabolites involvement in the formation of cell response to brassinosteroids.
Keywords: linoleic acid, lipoxygenase, 24-epibrassinolide, activation, cold stress.