Naslov
Inhibition of human blood acetylcholinesterase and butyrylcholinesterase by ethopropazine

Autori
Simeon-Rudolf, Vera ; Šinko, Goran ; Štuglin, Anita ; Reiner, Elsa

Izvornik
Croatica chemica acta (0011-1643) 74 (2001), 1; 173-182

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
acetylcholinesterase ; butyrylcholinesterase ; ethopropazine ; selective inhibition ; inhibition mechanism ; enzyme-inhibitor and enzyme-substrate dissociation constants

Sažetak
Inhibition of human erythrocyte acetylcholinesterase (AChE ; EC 3.1.1.7) and serum butyrylcholinesterase (BChE ; EC 3.1.1.8) by ethopropazine, 10-(2- diethylaminopropyl)phenothiazine hydrochloride, was measured with acetylthiocholine (ATCh) as substrate. Dissociation constants for the enzyme-inhibitor complexes were calculated from the effect of ATCh concentration on the apparent dissociation constants by applying non-linear regression to fit the model to experimental data. Inhibition of AChE revealed a competitive inhibition for two binding sites (Ka = 161 and Ki = 393 uM), inhibition of the atypical BChE was non-competitive (Ki = 7.5 uM) while that of the usual BChE was competitive (K(I) = 0.16 uM). At 20 uM ethopropazine and 1.0 mM acetylthiocholine (conditions used for differentiation between AChE and BChE activities) the erythrocyte AChE was 8% inhibited and the BChE phenotypes UU, UA, FF/FS, AF, AJ/AK and AA/AS between 98% and 74%.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti

POVEZANOST RADA