Abstract
THE fourth component of complement (C4) in human serum is a glycoprotein with a molecular weight of 209,000 and consists of three covalently linked polypeptide chains1–3. A three-chain structure in proteins is exceptional and there is a possibility that C4 is synthesised as one or two chains which are subsequently cleaved. This hypothesis is in agreement with Hall and Colten4, who presented evidence that polysomes from homogenates of guinea pig liver synthesised a precursor form of C4. This pro-C4 has a single polypeptide chain of the same molecular weight as intact serum C4. We report here the presence in human serum and plasma of a functionally inactive protein with antigenic properties of human C4, which does not dissociate in reducing conditions into the α, β and γ chains characteristic of haemolytically active serum C4. This molecule probably represents a circulating precursor form of C4, or material that has escaped from the cell without being processed.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Schreiber, R. D. & Müller-Eberhard, H. J. J. exp. Med. 140, 1324–1335 (1974).
Nagasawa, S. & Stroud, R. M. Fedn Proc. 35, 2473 (1976).
Gigli, I., Von Zabern, I. & Porter, R. Biochem. J. 165, 439–446 (1977).
Hall, R. E. & Colten, H. R. Proc. natn. Acad. Sci. U.S.A. 74, 1707–1710 (1977).
Lowry, O. H., Rosebrough, N. J., Farr, A. L. & Randall, R. J. J. biol. Chem. 193, 265–275 (1951).
Weber, K. & Osborne, M. J. biol. Chem. 244, 4406–4412 (1969).
Laurell, C. B. Analyt. Biochem. 10, 358 (1965).
Gorski, J. P. & Müller-Eberhard, H. J. J. Immunl. (in the press).
Bellamy, C. & Bornstein, P. Fedn Proc. 30, 1195 (1971).
Chan, S. J., Keim, P. & Steiner, D. Proc. natn. Acad. Sci. U.S.A. 73, 1964–1968 (1976).
Roos, M. H., Atkinson, J. P. & Shreffler, D. C. J. Immun. (in the press).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
GIGLI, I. A single chain precursor of C4 in human serum. Nature 272, 836–837 (1978). https://doi.org/10.1038/272836a0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/272836a0
This article is cited by
-
Post-transcriptional regulation of complement C4 in low C4-producing strain of mouse
Immunogenetics (1990)
-
Murine sex-limited protein (Slp) antigenic sites in human complement component C4
Immunogenetics (1983)
-
Precursor complement protein (pro-C4) is converted in vitro to native C4 by plasmin
Nature (1980)
-
The biochemistry of complement
Nature (1978)
-
Localisation of Chido and Rodgers determinants to the C4d fragment of human C4
Nature (1978)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.
