The influence of β-cyclodextrin on the kinetics of 1-en-dehydrogenation of 6α-methylhydrocortisone by Arthrobacter globiformis cells

Abstract

β-Cyclodextrin changes the kinetic peculiarities of microbial 1-en-dehydrogenation of 6α-methylhydrocortisone: the reaction rate, degree of conversion and respiratory-chain activity are increased. Respiratory-chain activity in the presence of β-cyclodextrin is increased both in the presence and in the absence of 6α-methylhydrocortisone. A mathematical model is proposed to describe the kinetics of the process. This model suggests the formation of different multi-component complexes consisting of inclusion complexes and the functional unit involving the enzyme and the respiratory chain. All the parameters of the model were estimated by data fitting. In the model framework the formation of multi-component complexes leads to an increase of the maximal reaction rate and to a decrease of substrate inhibition. An approach is suggested for optimisation of 6α-methylhydrocortisone 1-en-dehydrogenation in the presence of β-cyclodextrin. The optimal concentrations of 6α-methylhydrocortisone and β-cyclodextrin have been calculated.