Purification and characterisation of acetylcholinesterase isozymes from the latex of Synadenium grantii Hook, 'f'
Govindappa, T.; Govardhan, L.; Jyothy, P.S.; Veerabhadrappa, P.S.
Indian Journal of Biochemistry and Biophysics 24(4): 209-217
1987
ISSN/ISBN: 0301-1208 PMID: 3436630 Document Number: 295784
Three acetylcholinesterase isozymes were purified from Synadenium grantii latex by a combination of acetone fractionation, CM-Sephadex C-50 chromatography, Sephadex G-200 gel filtration and PE-Cellulose chromatography. The homogeneity of the isozymes was established by PAGE and isoelectrofocussing. The isoelectric pHs were found to be 5.0, 5.2 and 5.4. The molecule weight of each enzyme was estimated to be 70,000 by gel-filtration method. SDS-PAGE indicated that each enzyme consisted of two subunits of molecular weight around 35,000. These enzymes were glycoproteins and were more sensitive towards carbamate inhibitors compared to organophosphates. They exhibited substrate inhibition and showed identical substrate specificity and inhibitor sensitivity. The rate constants ki and I50 for different inhibitors were calculated. These three enzymes were considered to be charge isozymic forms of the latex acetylcholinesterase.