Evaluation of aflatoxin B1--acetylcholinesterase dissociation kinetic using the amperometric biosensor technology: prospect for toxicity mechanism.
Aflatoxins are group of secondary metabolites from moulds. The main toxic effect of aflatoxins on body is based on metabolic activation on cytochrome P450 system. Recently, some studies appointed at anticholinergic properties of aflatoxins and inhibition of acetylcholinesterases (AChE) was described. Inhibition is reversible; however, some questions arose. Is the interaction firmly enough to prevent distribution of aflatoxins in body? Could be AChE considered as a scavenger of aflatoxins? Amperometric biosensor with immobilized acetylcholinesterase was used for evaluation of aflatoxin B1 (AFB1) - AChE complex spontaneous dissociation, where AFB1 acts as an inhibitor. Displacement of solution with substrate and AFB1 by the intact one enabled estimation of dissociation kinetics. The dissociation rate constant k(dis) was found 0.0047 +/- 0.0005 s(-1). The half time (t(1/2)) of complex dissociation was 146 s. The achieved data appoint at fact that AChE could allow to distribute aflatoxins in body instead acting as a scavenger. Analytical impact of study is discussed, too.
Pohanka
Miroslav
M
Center of Advanced Studies, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 50001 Hradec Kralove, Czech Republic. rau@atlas.cz
Musilek
Kamil
K
Kuca
Kamil
K
D000110:Acetylcholinesterase / Q000737:chemistry* / Q000378:metabolism; D016604:Aflatoxin B1 / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods; D002800:Cholinesterase Inhibitors / Q000737:chemistry*; D004800:Enzymes, Immobilized / Q000737:chemistry*; D006801:Humans; D007700:Kinetics
D002800:Cholinesterase Inhibitors; D004800:Enzymes, Immobilized; D016604:Aflatoxin B1; D000110:Acetylcholinesterase