[Thermoinactivation of potato 5-lipoxygenase and effect of phosphatidic acid on activation energy of denaturation].

The investigation aim was to establish the structural-functional relations of individual lipid metabolism components: enzymes--lipoxygenases and membrane phospholipids. Influence of phosphatidic acid (PA)--allosteric activator of potato tuber 5-lipoxygenase (5-LO)--on thermoinactivation thermodynamic parameters of enzyme was studied. It was established that PA changes essentially the 5-LO thermostability, namely activation energy Ea of enzyme denaturation increases several times in this phospholipid presence.

[Interaction between 5-lipoxygenase and allosteric effector--sodium dodecyl sulfate].

The role of allosteric effector--sodium dodecyl sulfate (SDS) in the lipoxygenase catalysis in micelle system has been studied. The effect of the stable hydrophobic bis-nitroxides, blocking the free radical transformation, on the oxidation of linoleic acid or linoleic alcohol by 5-lipoxygenase from potato tuber has been investigated. The inhibiting effect of nitroxide compounds on oxidation of linoleic acid or linoleic alcohol by 5-lipoxygenase depends on SDS concentration.