ISSN 1392-0146
ISSN 2029-0578 (online)
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2008 m. Nr. 3
Electrochemical and spectrophotometric investigations of electron-transfer pathways in biocatalysis by PQQ-ADH
Julija RAZUMIENĖ, Edita VOITECHOVIČ, Irina BACHMATOVA, Liucija MARCINKEVIČIENĖ, Rolandas MEŠKYS, Valdas LAURINAVIČIUS
Aiming to investigate electron-transfer pathways in biocatalysis by pyrroloquinoline-quinonedependent alcohol dehydrogenase (PQQ-ADH), the inhibition of hemes c of PQQ-ADH by CO was carried out. The inactivation kinetics was studied using a group of one- and two-electron acceptors: potassium ferricyanide (PF) and dichlorophenolindophenol (DCPIP). The inactivation constants (kin), that characterize the PQQ-ADH inactivation rate due to inhibition of hemes c were calculated. The results showed that bioelectrocatalysis by PQQ-ADH proceeds via an energetically favourable way of internal mediation; however, an alternative electron transfer switches on when the usual pathway is blocked. A mechanism of the possible electron-transfer pathways in biocatalysis by PQQ-ADH is proposed.
Keywords: PQQ-dependent alcohol dehydrogenase, electron transfer, biocatalysis, inactivation kinetics
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