Mechanism of Oxygen Activation in Hydroxylation Reactions Involving Cytochrome P450

In the 20-37 °c range the kinetics of cyclohexene epoxidation, naphthalene and cyclohexane hydroxylation and oxidative demethylation of a group of amines in the presence of rat liver microsomes, NADPH and 0 2 has been studied

Mechanism of Oxygen Activation in Hydroxylation Reactions Involving Cytochrome P450

In the 20-37 °c range the kinetics of cyclohexene epoxidation, naphthalene and cyclohexane hydroxylation and oxidative demethylation of a group of amines in the presence of rat liver microsomes, NADPH and 0 2 has been studied

Влияние диметилформамида на пероксидазное окисление тетраметилбензидина и его ингибирование

The kinetics of the peroxidase-catalyzed tetramethylbanzidine (TMB) oxidation has been studied in phosphate-citrate buffer (pH 6.0 and 6.4), containing 3-25 % of dimethylformamide (DMF), at 20 °C. The relationship between DMF concentration and kinetic parameters kcat, KM and kcat/KM has been determined. It has been shown that lg kcat linearly decreased with increasing DMF concentration, whereas KM value did not change. Kinetics of peroxidase-dependent TMB oxidation inhibition by two synthetic sulphur-containing α-tocopherol analogs at various DMF concentrations (3-25%) has been studed, and the inhibition constants Ki have been determined. It has been shown that with increasing DMF concentration, Ki values decreased from 15.8 to 3.2 μM. This fact is accounted for by DMF effect on the structures of peroxidase and inhibitors, as well as on their interaction, where the electrostatic interactions play a great part, since lgKi is linearly dependent on (ε-1)/(2ε+1), where ε is the dielectric constant of the reaction medium.В смеси фосфатно-цитратного буфера (рН 6,0 и 6,4) с диметилформамидом (ДМФ, 3-30 %) при 20 °С изучена кинетика пероксидазного окисления тетраметилбензидина (ТМБ) и определены кинетические параметры kcat, константа Михаэлиса KM и kcat/ KM в зависимости от концентрации ДМФ. Показано, что lgkcat линейно уменьшается с ростом содержания ДМФ, а KM практически не зависит от него. Изучена кинетика ингибирования окисления ТМБ двумя синтетическими аналогами α-токоферола и определены константы ингибирования Ki, меняющиеся с ростом ДМФ от 15,8 до 3,2 мкМ, что объясняется действием ДМФ на структуру пероксида-зы и ингибиторов, а также их взаимодействие, в котором важная роль принадлежит электростатическим силам, так как lgKi линейно зависит от (ε-1)/(2ε+1), где ε - диэлектрическая проницаемость среды