[Potentiometric electrodes for determining choline, butyrylcholine and cholinesterase inhibitors]. / Potentsiometricheskie élektrody dlia opredeleniia kholina, butirilkholina i ingibitorov kholinésteraz.

Potentiometric choline electrodes were developed on the basis of the mediator-free bioelectrocatalysis. The electrodes made of a composite carbon-polymer material contain choline oxidase and peroxidase coimmobilized on the surface of the electrode. The rate of the potential increase was shown to be proportional to the choline concentration within a broad range of variation. Coupling of choline-sensitive electrodes with butyrylcholinesterase makes possible both the direct detection of butyrylcholine and analysis of butyrylcholinesterase inhibitors.

[Laccase from Coriolus hirsutus--a new marker enzyme for immunoenzyme analysis]. / Lakkaza Coriolus hirsutus--novyi ferment-marker dlia immunofermentnogo analiza.

A new immunochemical reagent is proposed which contains laccase, isolated from the culture liquid of the basidial fungus Coriolus hirsutus, as a marker enzyme. The feasibility of immunolaccase conjugates for different variants of immunoassay, i.e. "sandwich", competitive and indirect, is demonstrated. The comparison of immunolaccase and immunoperoxidase conjugates showed that the absolute sensitivity of laccase-antibody conjugates was 3 times higher than that of antibody-peroxidase conjugates (7.7 x 10(-11) M and 2.3 x 10(-10) M, respectively). The assay based on antibody-laccase conjugates is simpler than that employing antibody-peroxidase conjugates, since in the former case air oxygen in used as the second substrate of the enzymatic reaction.

[The use of bioelectrochemical systems in steroid biosynthesis]. / Ispol'zovanie bioélektrokhimicheskikh sistem dlia sinteza steroidov.

The feasibility of electrosynthesis involving the use of biocatalysts has been demonstrated in a model reaction of hydrocortisone oxidation to prednisolone catalyzed by Arthrobacter globiformis cells. Electrochemical regeneration of phenazine methosulfate, an artificial electron acceptor, was performed, using electrodes made of different materials. Transformation products were analyzed by high performance liquid chromatography.