143
were excluded from the column and hence no immunoglobulin appeared
in the volumes expected to contain < 200,000 molecular material.
If on the other hand unreduced specific immune precipitates, as de
picted in Figure 21 (left panel) for WBC lysates, are dissolved in
8 M urea, 2% SDS and subjected to SDS-agarose-acrylamide electrophore
sis some radioactivity was localized to gel slices expected to contain
180,000 molecular weight material (based upon a simultaneously run
shark 7S Ig marker). Immune precipitates of radio-labeled thymus,
spleen, and kidney lysates also gave demonstrable a. 180,000 molecudar
weight material in such experiments although the proportion of higher
molecular weight material was quite variable. In fact in some cases,
especially with kidney material, > 70% of the applied radioactivity was
of > 180,000 molecular weight. These findings were in contrast to those
with precipitates of mouse lysates wherein 85% of the applied radioac
tivity was localized as a single a- 180,000 molecular weight component.
Thus faced with the problem of multiple components (including an
apparently high molecular weight peptide seen on gel profiles of re
duced material), specific immune precipitates of radio-labeled blue-
gill cell lysates were dissolved in urea-SDS and subjected to gel fil
tration on Biogel 5M equilibrated with 0.5% SDS. As depicted in Figure
21 (right panel) radioactivity originally derived from WBC (and also
with specific precipitates from thymus, spleen, and kidney cell lysates)
was resolved into two major components, i.e. one in a volume expected
to contain a, 180,000 molecular weight proteins (designated pool 2) and
one composed of larger material (designated pool 1). Each of these two
pools were concentrated by pressure dialysis, extensively reduced and
subjected to SDS-acrylamide electrophoresis. As depicted in Figure 22