Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published January 1979 | Published
Journal Article Open

Copurification of actin and desmin from chicken smooth muscle and their copolymerization in vitro to intermediate filaments


Desmin is a 50,000-mol wt protein that is enriched along with 100-A filaments in chicken gizzard that has been extracted with 1 M KI. Although 1 M KI removes most of the actin from gizzard, a small fraction of this protein remains persistently insoluble, along with desmin. The solubility properties of this actin are the same as for desmin: they are both insoluble in high salt concentrations, but are solubilized at low pH or by agents that dissociate hydrophobic bonds. Desmin may be purified by repeated cycles of solubilization by 1 M acetic acid and subsequent precipitation by neutralization to pH 4. During this process, a constant nonstoichiometric ratio of actin to desmin is attained. Gel filtration on Ultrogel AcA34 in the presence of 0.5% Sarkosyl NL-97 reveals nonmonomeric fractions of actin and desmin that comigrate through the column. Gel filtration on Bio-Gel P300 in the presence of 1 M acetic acid reveals that the majority of desmin is monomeric under these conditions. A small fraction of desmin and all of the actin elute with the excluded volume. When the acetic acid is removed from actin-desmin solutions by dialysis, a gel forms that is composed of filaments with diameters of 120-140 A. These filaments react uniformly with both anti-actin and anti-desmin antiserum. These results suggest that desmin is the major subunit of the muscle 100-A filaments and that it may form nonstoichiometric complexes with actin.

Additional Information

© 1979 by The Rockefeller University Press. Received for publication 16 March 1978, and in revised form 11 July 1978. We would like to thank the two reviewers for their time and effort and their many helpful comments. This work was supported by grant PHS-GM 06965-18 from the National Institutes of Health, and also by grants from the Muscular Dystrophy Association of America and the American Cancer Society.

Attached Files

Published - HUBjcb79.pdf


Files (4.7 MB)
Name Size Download all
4.7 MB Preview Download

Additional details

August 22, 2023
October 16, 2023