1998 - [Phenserine][*****][human erythrocyte acetylcholinesterase inhibition]
1: Biochem Biophys Res Commun 1998 Jul 9;248(1):180-5 Related Articles, Links
Kinetics of human erythrocyte acetylcholinesterase inhibition by a novel derivative of physostigmine: phenserine.
al-Jafari AA, Kamal MA, Greig NH, Alhomida AS, Perry ER.
Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia. JAFARI@KSU.EDU.SA
The effect of phenserine, a novel cholinesterase inhibitor, was assessed for the first time on kinetic parameters of human erythrocyte acetylcholinesterase (AChE).
Phenserine (0.025-0.40 microM) inhibited the activity of human erythrocyte AChE in a concentration-dependent fashion, the IC50 was 0.0453 microM.
The Michaelis-Menten constant (K(m)) for the hydrolysis of acetylthiocholine iodide was found to be 0.124 mM and the Vmax was 0.980 mumol/min/mg protein. Dixon as well as Lineweaver-Burk plots and their secondary replots indicated that the nature of the inhibition was of the noncompetitive type. The value of Ki was estimated as 0.048 microM by the primary and secondary replots of the Dixon as well as secondary replots of the Lineweaver-Burk plot. A novel relationship between Ki and substrate concentration was also identified which permits more precise prediction of the specific type of noncompetitive inhibition of various enzymes by a wide variety of drugs, chemicals and, in some circumstances, by their own substrates.
PMID: 9675107 [PubMed - indexed for MEDLINE]
ncbi.nlm.nih.gov |
