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PURIFICATION AND PROPERTIES OF MULTIPLE FORMS OF BRAIN ACETYLCHOLINESTERASE (EC 3.1.1.7) 1
Author(s) -
Chan S. L.,
Shirachi D. Y.,
Bhargava H. N.,
Gardner E.,
Trevor A. J.
Publication year - 1972
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1972.tb03812.x
Subject(s) - acetylcholinesterase , chromatography , homogenization (climate) , chemistry , isoelectric focusing , agarose , size exclusion chromatography , enzyme , molecular mass , acetylthiocholine , fractionation , specific activity , affinity chromatography , biochemistry , ammonium , centrifugation , hydrolysis , aché , polyacrylamide gel electrophoresis , biology , biodiversity , organic chemistry , ecology
—Approximately 70 per cent of the total AChE of bovine brain tissue was solubilized by repeated homogenization and centrifugation in 0.32 m sucrose containing EDTA. After ammonium sulphate fractionation, application of the enzyme preparation to an agarose affinity gel column effected a 700‐fold purification. Subsequent molecular filtration separated three active forms of AChE with molecular weights of 130,000, 270,000 and 390,000 with an average specific activity of 575 mmol of acetylthiocholine hydrolysed/mg of protein/h. The complete procedure represented an approximate 23,000‐fold purification of the enzyme from that in the original tissue homogenate. The three forms of AChE exhibited certain differences in properties, including apparent K m values, pH optima and sensitivity to inhibitory agents. Ancillary studies on less purified enzyme preparations by use of polyacrylamide gel electrophoresis and isoelectric focusing techniques also suggested that brain AChE exists in multiple forms.