TY - JOUR
T1 - Subunit heterogeneity of acetylcholinesterase
AU - Chen, Yueh T.
AU - Rosenberry, Terrone L.
AU - Chang, Hai Won
N1 - Funding Information:
1 This work was supported, in part, by U.S. Public Health Service Grant NS-03304, by the National Science Foundation Grant NSF-GB-31122X1, and by the New York Heart Association, Inc. 2 Present address: Research Institute for Skeletomuscular Diseases of the Hospital for Joint Diseases, 1919 Madison Ave., New York, NY 10035. 3 To whom requests for reprints should be sent.
PY - 1974/4
Y1 - 1974/4
N2 - Several different preparations of purified 11 S acetylcholinesterase have been examined for structural heterogeneity. While no contaminant protein was observed in any of the preparations, minor isozymic forms with catalytic activity were observed in addition to the major component both in polyacrylamide gel electrophoresis and in isoelectric focusing. Major differences in the relative composition of the disulfide-reduced polypeptides among the preparations were found by gel electrophoresis in sodium dodecyl sulfate. Several characteristics of these differences strongly suggest that they derive from a proteolytic fragmentation of a single subunit species. In particular, the apparent fragmentation in the crude enzyme solution is inhibited by benzethonium chloride, an inhibitor of proteolysis which also prevents the conversion of 18, 14, and 8 S acetylcholinesterase species to the 11 S form in fresh electric tissue extracts. No significant differences in the enzyme specific activity are observed among the preparations, an observation which indicates that fully active native enzyme molecules are composed of subunits which are heterogeneous with respect to discrete points of polypeptide cleavage.
AB - Several different preparations of purified 11 S acetylcholinesterase have been examined for structural heterogeneity. While no contaminant protein was observed in any of the preparations, minor isozymic forms with catalytic activity were observed in addition to the major component both in polyacrylamide gel electrophoresis and in isoelectric focusing. Major differences in the relative composition of the disulfide-reduced polypeptides among the preparations were found by gel electrophoresis in sodium dodecyl sulfate. Several characteristics of these differences strongly suggest that they derive from a proteolytic fragmentation of a single subunit species. In particular, the apparent fragmentation in the crude enzyme solution is inhibited by benzethonium chloride, an inhibitor of proteolysis which also prevents the conversion of 18, 14, and 8 S acetylcholinesterase species to the 11 S form in fresh electric tissue extracts. No significant differences in the enzyme specific activity are observed among the preparations, an observation which indicates that fully active native enzyme molecules are composed of subunits which are heterogeneous with respect to discrete points of polypeptide cleavage.
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U2 - 10.1016/0003-9861(74)90330-0
DO - 10.1016/0003-9861(74)90330-0
M3 - Article
C2 - 4839042
AN - SCOPUS:0016372451
SN - 0003-9861
VL - 161
SP - 479
EP - 487
JO - Archives of Biochemistry and Biophysics
JF - Archives of Biochemistry and Biophysics
IS - 2
ER -