Journal of Clinical Investigation · 1974 · 23 citations · 35 references
The serum of a patient (L'ec) with an IgM lambda miionioclonial protein was inoted to bind albumiln on imnmunoelectroplhoresis. Analytical ultracentri- fugation of the L'ec serum demonstrated 23S and 12S peaks, but no 4S (albumin) boundary. Immunologically identical 20S and 9S IgM proteins were isolated from the serum and the addition in vitro of either the patient's albumin or albumin isolated from normal serum was shown to reconstitute the 23S and 12S boundaries. The binding of high molecular weight IgM to albumin was demonstated by Sephadex G200 chromatography with "I-labeled albunmin and isolated IgM. Immunoelectrophoresis of the L'ec IgMI developed with aggregated al- bumin (reverse imilmulnoelectrophoresis) also demon- strated the binding of albumin to TgM\. That all of the patient's IgM coilmplexe(I wNith albumin was shown by affinity chromatography emiiployilng an aggregated al- h)umiini-immiiiiunoadsorbenit column. Binding was shown to be of the noncovalent type by polyacrylamide gel elec- trophoresis in 8 M urea. With hot trypsin proteolysis, Fab,u and Fc,u5 fragments were isolated, and monomer albumin was shown to complex only with the Fabyi frag- ment by both analytical ultracentrifugation and molec- ular sieve chromatogaphy employing "zI-labeled Fab fragments. 1 mol of FabiA fragment bound 1 mol of monomer albumin.
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