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Kolas I.K.,Grodno State Agrarian University | Makarchikov A.F.,Grodno State Agrarian University
Ukrainian Biochemical Journal | Year: 2015

The enzymes involved in thiamine triphosphate (ThTP) metabolism in birds are not characterized so far. The aim of the present work was to study some properties of ThTPase in chicken liver. In liver homogenate, ThTPase activity has been found to display a bell-like pH-profile with a maximum of 5.5-6.0 Low activity was observed without divalent metal ions, while the addition of Mg2+ or Ca2+, each at 5 mM concentration, enhanced the rate of ThTP hydrolysis by a factor of 17-20. In the presence of 5 mM Mg2+ an apparent Km of the enzyme for ThTP was estimated by the method of non-linear regression as well as from the Hanes plot to be 1.7-2.2 mM. Monovalent anions such as I–, SCN–, NO3 –, Br–, Cl– (at 150 mM concentration) showed inhibitory effect decreasing the rate of ThTPase reaction by 20-60%. After the homogenate was centrifuged, more than 85% of ThTPase activity was revealed in the fraction of insoluble particles indicating a membrane localization of the enzyme. The precipitate treatment with 1% sodium deoxycholate caused about 53% solubilization of the activity. During Toyopeal HW-55 chromatography, ThTPase activity was eluted simultaneously with ATPase and ITPase peaks in the void volume of the column. Thus, a non-specific high molecular mass protein complex seems to be involved in ThTP hydrolysis in the chicken liver. The chicken liver phosphatase is clearly distinguishable from all membrane-bound ThTPases reported previously. © 2015, Natsional'na Akademiya Nauk Ukrainy. All Rights Reserved. Source


Kubyshin V.L.,Grodno State Agrarian University | Tomashova A.V.,Grodno State Agrarian University | Kulesh I.V.,Grodno State Agrarian University | Gorbach Z.V.,Grodno State Agrarian University
Ukrain'skyi Biokhimichnyi Zhurnal | Year: 2012

The work deals with isolation of transketolase from the rat liver by means of ion-exchange chromatography and substrate elution of enzyme. Experimental data on the regulation of transketolase activity with thiamin pyrophosphate (TPP) and its anticoenzyme analogues are presented. The kineticsof dissociation of holo-TK at pH 4.0 and 5.0 and reactivation of apo-TK at a wide variation of the concentration of TPP and its derivatives with anticoenzyme properties has been studied. The dissociation of holo-TK into apoenzymes and coenzymes at the specified values of pH is characterised by most evident diphasic nature, both fast and slow process being observed. The most part of enzymic activity slowdown falls on the fast phase, while the remaining 20-30% take place within the slow phase. The kinetics research findingsillustrate the nonidentity of enzyme active sites with respect to TPP binding with transketolase. The Km values for TPP both per the first and second active sites equalled 0.3-4.5 μM and 1.3-19.7 μM, accordingly. Source


Kravchenko V.I.,Grodno State Agrarian University | Struk V.A.,Grodno State Agrarian University | Avdejchik S.V.,Grodno State Agrarian University | Ryskulov A.A.,Grodno State Agrarian University
17th International Colloquium Tribology 2010 - Solving Friction and Wear Problems | Year: 2010

In multilayer coatings of multiphase polymer-oligomer composite layer performs the function of extreme pressure element, which prevents grasping and tearing in depth at the spots of actual contact. Source


Struk V.A.,Grodno State Agrarian University | Ovchinnikov E.V.,Grodno State Agrarian University | Kravchenko V.I.,Grodno State Agrarian University | Avdejchik S.V.,Grodno State Agrarian University | Ryskulov A.A.,Grodno State Agrarian University
17th International Colloquium Tribology 2010 - Solving Friction and Wear Problems | Year: 2010

Polytetrafluoroethylene nanodimension particles obtained by termogas dynamics synthesis technology structure and tribotechnical characteristics are investigated. It is shown that isolated particles corresponds oligomeric and polymeric fractions set which provides possibility of the thin composite films on solid surfaces decreasing friction and wear formation. Source

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