title: Direct electrochemistry of heme multicofactor-containing enzymes on alkanethiol-modified gold electrodes.
abstract: Direct electrochemistry of heme multicofactor-containing enzymes, e.g., microbial theophylline oxidase (ThOx) and D-fructose dehydrogenase (FDH) from Gluconobacter industrius was studied on alkanethiol-modified gold electrodes and was compared with that of some previously studied complex heme enzymes, specifically, cellobiose dehydrogenase (CDH) and sulphite oxidase (SOx). The formal redox potentials for enzymes in direct electronic communication varied for ThOx from -112 to -101 mV (vs. Ag|AgCl), at pH 7.0, and for FDH from -158 to -89 mV, at pH 5.0 and pH 4.0, respectively, on differently charged alkanethiol layers. Direct and mediated by cytochrome c electrochemistry of FDH correlated with the existence of two active centres in the protein structure, i.e., the heme and the pyrroloquinoline quinone (PQQ) prosthetic groups. The effect of the alkanethiols of different polarity and charge on the surface properties of the gold electrodes necessary for adsorption and orientation of ThOx, FDH, CDH and SOx, favourable for the efficient electrode-enzyme electron transfer reaction, is discussed.
authors.affiliation: Group of Bioinformatics, Weblab, IT Centre, Voskhod 26a, Novosibirsk 630102, Russia. ferapontova@nsk.fio.ru
authors.forename: Elena
authors.initials: E
authors.lastname: E Ferapontova
authors.forename: Lo
authors.initials: L
authors.lastname: Gorton
mesh_terms: D000327:Adsorption; D002237:Carbohydrate Dehydrogenases / Q000737:chemistry*; D003543:Cysteamine / Q000737:chemistry; D045304:Cytochromes c / Q000737:chemistry; D004563:Electrochemistry; D004566:Electrodes; D004579:Electron Transport; D006046:Gold; D006418:Heme / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D010088:Oxidoreductases / Q000737:chemistry*; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000737:chemistry; D013053:Spectrophotometry; D013438:Sulfhydryl Compounds / Q000737:chemistry
chemical_list: D013438:Sulfhydryl Compounds; D006418:Heme; D003543:Cysteamine; D006046:Gold; D045304:Cytochromes c; D010088:Oxidoreductases; D002237:Carbohydrate Dehydrogenases; C028761:D-fructose 5-dehydrogenase; C019859:cellobiose-quinone oxidoreductase; C073406:theophylline oxidase; D050862:Oxidoreductases Acting on Sulfur Group Donors