Inhibition of Butyrylcholinesterase with Fluorobenzylcymserine, An Experimental Alzheimer's Drug Candidate: Validation of Enzoinformatics Results by Classical and Innovative Enzyme Kinetic Analyses.
BACKGROUND
Selective butyrylcholinesterase (BuChE)-inhibition, increases acetylcholine (ACh) levels. In rodents, this inhibition is known to boost cognition. Also, this occurs without the typical unwanted adverse effects of acetylcholinesterase-inhibitors or AChE-Is. The novel compound, fluorobenzylcymserine (FBC), is derived from our effort to design a selective BuChE-inhibitor. Also, we wanted to check whether butyrylcholinesterase-inhibitors (BuChE-Is) possessed an edge over AChE-Is in Alzheimer's disease (AD) in terms of efficacy and/or tolerance.


METHODS
FBC was synthesized as reported earlier while enzymatic activity of BuChE was calculated by Ellman-technique. Molecular docking was performed using Autodock4.2. We applied classical as well as innovative analyses of enzyme-kinetics for exploring "FBC:human BuChE-interaction". The mode of inhibition and kinetic parameters were also determined.


RESULTS
Docking results displayed two strong interacting sites for FBC. One of these binding sites was previously identified as a deep narrow groove having polar aromatic residues while a second site was identified during this study which displayed better interaction and was lined with aliphatic and sulphur containing residues. At low concentrations of BuChE, the IC50 was found to be very low i.e. 4.79 and 6.10 nM for 12 and 36 µg, respectively, whereas it increased exponentially by increasing the units of BuChE.


CONCLUSIONS
These analyses indicate that FBC is an interesting AD drug candidate that could provide a potent and partial mixed type of inhibition of human BuChE.
King Fahd Medical Research Center, King Abdulaziz University, Jeddah. Saudi Arabia.
Mohammad A
MA
Kamal
Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah. Saudi Arabia.
Shazi
S
Shakil
Department of Biological Science, COMSATS, Islamabad, Pakistan; 4Novel Global Community Educational Foundation, New South Wales. Australia.
Muhammad S
MS
Nawaz
Drug Design & Development Section, Laboratory of Neurosciences, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224. United States.
Qian-Sheng
QS
Yu
Drug Design & Development Section, Laboratory of Neurosciences, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224. United States.
David
D
Tweedie
Department of Medical & Molecular Biosciences, Faculty of Science, University of Technology, Sydney, NSW. Australia.
Y
Y
Tan
Department of Medical & Molecular Biosciences, Faculty of Science, University of Technology, Sydney, NSW. Australia.
Xianqin
X
Qu
Drug Design & Development Section, Gerontology Research Center, Room 4B02, 5600 Nathan Shock Dr., Baltimore, MD 21224. United States.
Nigel H
NH
Greig
D000544:Alzheimer Disease / Q000188:drug therapy*; D001665:Binding Sites; D002091:Butyrylcholinesterase / Q000187:drug effects* / Q000378:metabolism; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D006801:Humans; D020128:Inhibitory Concentration 50; D007700:Kinetics; D062105:Molecular Docking Simulation; D010830:Physostigmine / Q000031:analogs & derivatives* / Q000494:pharmacology
D002800:Cholinesterase Inhibitors; C509735:cymserine; D010830:Physostigmine; D002091:Butyrylcholinesterase
Alzheimer's disease; anticholinesterase; butyrylcholinesterase; cymserine; docking; enzyme inhibition kinetics; fluorobenzylcymserine