Heterogeneity of Human Erythrocyte Acetylcholinesterase. Individual Variation Revealed by DEAE-Cellulose Chromatography and Polyacrylamide Gel Disc Electrophoresis

Abstract

Acetylcholinesterase (EAChE; acetylcholine acetyl hydrolase, EC 3.1.1.7) was prepared from the erythrocyte membrane of Chinese adult males, and solubilised with 1% Triton X-100 in 20 mmol/1 phosphate buffer, pH 7.4. Chromatography of the preparation on DEAE-cellulose, using a linear gradient of increasing NaCl concentration, yielded four reproducible elution patterns with differing peaks of enzyme activity. On the basis of the number and position of the enzymatically active peaks, the individuals could be grouped into four types : type 1 : with 4 peaks of activity, EAChE 1, EAChE 2, EAChE 3, EAChE 4; type II: with 3 peaks of activity, EAChE 1, EAChE 3, EAChE 4; type III: with 3 peaks of activity, EAChE 1, EAChE 2, EAChE 4; type IV : with 3 peaks of activity, EAChE 1, EAChE 2, EAChE 3. Each enzyme entity could be eluted in the similar position on rechromatography with loss of activity. When the same samples were subjected to disc electrophoresis on 5% polyacrylamide gel at pH 8.6, three different repeatable patterns were observed. A distinct band (Ch(4)) at the origin, containing a largest proportion of the enzyme activity, was present in all the samples. One group contained three additional bands of activity Ch(3), Ch(2), Ch(1), while the other two groups had either Ch(2) and Ch(1) or Ch(3) and Ch(1) in addition to the Ch(4) band. No correlation was apparent between individuals typed by DEAE-cellulose chromatography and those typed by disc electrophoresis; further no correlation between either of these types and blood group was apparent.