Multiple forms of acetylcholinesterase from human erythrocytes

Abstract

1. Acetylcholinesterase from human erythrocytes was solubilized with Triton X-100 in strong salt solution and partially purified by (NH(4))(2)SO(4) fractionation. This preparation showed three main bands of enzyme activity after electrophoresis on polyacrylamide gel and incubation with either alpha-naphthyl acetate or acetylthiocholine as enzyme substrate. Two of the multiple forms were completely inhibited by 10mum-eserine and one only partially. Treatment with neuraminidase had no effect on the electrophoretic pattern; therefore sialic acid does not appear to determine or affect the ratios of the acetylcholinesterase multiple forms, unlike those of the serum cholinesterase. 2. Chromatography of the preparation on Sephadex G-200 revealed one major peak of enzyme activity and a suggestion of two minor zones of mol.wt. 546000, 184000 and 93000 (i.e. in the proportion 6:2:1). The main peak was almost completely separated from the Triton X-100 and the overall purification was about 600-fold. Further attempts to purify the enzyme by absorption on calcium phosphate gels were unsuccessful. 3. Electrophoresis of the enzyme preparation on a polyacrylamide gradient for 24h revealed three main bands that corresponded to the three values for molecular weights obtained by column chromatography. After 70h of electrophoresis a further three zones of activity developed making six molecular entities, the molecular weights of which were simple multiples of a monomer, thus resembling the cholinesterase found in serum.

Acetylcholine and choline effects on erythrocyte nitrite and nitrate levels

“…The vascular relaxation verified in the presence of ACh is dependent on the integrity of the endothelium (Furchgott and Zawadzki, 1980). Erythrocytes are peripheral blood elements with more AChE content in the membranes (Wright and Plummer, 1973). However, the function of AChE in erythrocytes is still unknown and it is the object of much research investigation.…”

The Ubiquity Nature of Acetylcholine

“…Red blood cells account for the blood elements with highest expression of membrane-bound acetylcholinesterase [12]. The enzyme AChE has the particularity to be inhibited by high concentrations of its own substrate, ACh.…”

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

“…The demonstration of several isozymic components of Triton X-100-solubilised erythrocyte acetylcholinesterase (EAChE0) by various separation techniques is well documented [1,7,[19][20][21]. The work of Safai and Cortner [20] in this aspect is particularly of interest.…”