Journal of Neuroscience, Vol 5, 1955-1964, Copyright © 1985 by Society for Neuroscience
Molecular weight determinations of soluble and membrane-bound fractions of choline O-acetyltransferase in rat brain
M Badamchian and PT Carroll
Three fractions of choline O-acetyltransferase (ChAT) (EC 2.3.1.6) were
solubilized from a nerve ending fraction of rat forebrain using three
sequential washes of an increasingly chaotrophic nature (100 mM sodium
phosphate, pH 7.4; 500 mM NaCl; 2% Triton DN-65) as previously described
(Benishin, C.G., and P.T. Carroll (1983) J. Neurochem. 41: 1030-1039). The
molecular weights of the soluble (NaP) and membrane- bound fractions (NaCl
and 2% Triton DN-65) of ChAT, following partial purification, were
determined using either gel filtration on Sephadex G- 200, G-100 Superfine,
or sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)
followed by "Western blotting" and immunochemical visualization of ChAT
with four different anti-ChAT monoclonal antibodies (Ab8, Ab9, 4D7, and
1E6). Results obtained with gel filtration indicated that the NaP- and
Triton DN-65-solubilized fractions of ChAT had molecular weights in the
range of 73,000 to 78,000, whereas the NaCl-solubilized fraction of ChAT
had a molecular weight in the range of 230,000 to 240,000. Results obtained
with SDS- PAGE and Western blotting indicated that all three fractions of
ChAT were composed of the same nonidentical subunits.