О. О. Моlodchenkova¹, V. G. Аdamovskaya¹, L. Y. Ciselskaya¹,
L. Ya. Bezkrovnaya¹, T. V. Kаrtuzova¹, V. B. Iablonska²

¹Plant Breeding and Genetics Institute-National Center of Seed
and Cultivar Investigation, Ukraine;
e-mail: olgamolod@ukr.net;
²Оdessa National Medical University, Ukraine;
e-mail: 93vi_63@mail.ru

Lipoxygenase from wheat seedlings in normal conditions, infected by Fusarium graminearum and  treated by salicylic acid was isolated. The isolated enzyme was purified by the methods of salting-out (60% ammonium sulphate), dialysis, gel-filtration and ion-exchange chromatography. Specific activity of the purified enzyme was 8.0-12.5 ΔЕ₂₃₄/mg of protein, degree of purification – 11.6-15.3 times. The enzyme yield was 18.3-27.9%. Molecular mass of lipoxygenase is 90 kDa, amino acid composition is distinguished by a high content of glutamic acid, proline, valine, isoleucine, leucine and low level of histidine, tyrosine, phenylalanine, threonine, tryptophan, cystein. Research of lipoxygenase substrate dependence indicated that the enzyme  catalysed with the maximum velocity of the reaction of arachidonic acid oxidation at a substrate concentration of 4.5 mM at pH 7.2, the reaction of linoleic acid oxidation at a substrate concentration of 4.5 mM at pH 7.2 and the reaction of linolenic acid oxidation at a substrate concentration of 9.0 mM at pH 8.0. The change of wheat lipoxygenase activity depending on genotype resistance to Fusarium graminearum and millieu of germination was shown. One of the manifestations of the protective effect of salicylic acid is its ability to induce changes of lipoxygenase activity.