Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Isolation of human complex-forming glycoprotein, heterogeneous in charge (protein HC), and its IgA complex from plasma. Physiochemical and immunochemical properties, normal plasma concentration

Grubb, A O LU orcid ; López, C ; Tejler, L and Mendez, E (1983) In The Journal of biological chemistry 258(23). p.707-14698
Abstract

Human complex-forming glycoprotein, heterogeneous in charge (protein HC) has previously been isolated from urine and immunochemically shown to be present in low and high molecular weight forms in blood plasma (Tejler, L., and Grubb, A. O. (1976) Biochim. Biophys. Acta 439, 82-94). In the present work, the major low and high molecular weight forms of the protein were isolated from plasma by immunosorption followed by gel chromatography. The plasma low molecular weight protein HC and the urinary protein had similar, if not identical, molecular weight, amino acid composition, NH2-terminal and carboxyl-terminal amino acid sequences and electrophoretic mobility. The low molecular weight plasma protein HC carried a yellow chromophore like the... (More)

Human complex-forming glycoprotein, heterogeneous in charge (protein HC) has previously been isolated from urine and immunochemically shown to be present in low and high molecular weight forms in blood plasma (Tejler, L., and Grubb, A. O. (1976) Biochim. Biophys. Acta 439, 82-94). In the present work, the major low and high molecular weight forms of the protein were isolated from plasma by immunosorption followed by gel chromatography. The plasma low molecular weight protein HC and the urinary protein had similar, if not identical, molecular weight, amino acid composition, NH2-terminal and carboxyl-terminal amino acid sequences and electrophoretic mobility. The low molecular weight plasma protein HC carried a yellow chromophore like the urinary protein, but its molar extinction coefficient at 280 nm was lower and its charge heterogeneity less pronounced than that of urinary protein HC. The plasma high molecular weight protein HC had a hydrodynamic volume which was greater than that of monomeric IgA but smaller than that of dimeric IgA. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the isolated high molecular weight protein followed by electrophoretic blotting and immunochemical analysis demonstrated that the protein contained four polypeptide chains: two light immunoglobulin chains (Mr = 23,000), one IgA alpha-chain (Mr = 54,000), and one chain with Mr approximately 90,000 which carried both alpha-chain and protein HC antigenic determinants. Whether the protein HC X IgA complex is a functionally significant part of the humoral immune system cannot be decided without further experimentation, but the complex was found to be completely absent from the blood plasma of patients with a selective deficiency of IgA-secreting immunocytes. The isolated low and high molecular weight plasma protein HC components were used as standard proteins in the construction of a quantitative crossed immunoelectrophoretic assay for the simultaneous quantitation of the two major protein HC components in blood plasma. The plasma concentrations of the low and high molecular weight protein HC components were measured by this method in 13 healthy Caucasians. The results for the low molecular weight protein HC were: mean, 20.3 mg/liter, S.D., 3.2 mg/liter, range, 13.6-26.0 mg/liter; and for the protein HC X IgA complex: mean, 293 mg/liter, S.D., 176 mg/liter, range, 36-620 mg/liter.

(Less)
Please use this url to cite or link to this publication:
author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Adult, Alpha-Globulins/isolation & purification, Amino Acids/analysis, Carbohydrates/analysis, Cyanogen Bromide, Electrophoresis, Agar Gel, Humans, Immunodiffusion, Immunoelectrophoresis, Two-Dimensional, Immunoglobulin A/metabolism, Molecular Weight
in
The Journal of biological chemistry
volume
258
issue
23
pages
707 - 14698
publisher
American Society for Biochemistry and Molecular Biology
external identifiers
  • pmid:6196366
  • scopus:0021075711
ISSN
0021-9258
DOI
10.1016/S0021-9258(17)43919-6
language
English
LU publication?
yes
id
44cd1bb1-44b3-49f8-95e4-91d98c5a5fb8
date added to LUP
2021-10-22 15:41:39
date last changed
2024-01-12 02:54:42
@article{44cd1bb1-44b3-49f8-95e4-91d98c5a5fb8,
  abstract     = {{<p>Human complex-forming glycoprotein, heterogeneous in charge (protein HC) has previously been isolated from urine and immunochemically shown to be present in low and high molecular weight forms in blood plasma (Tejler, L., and Grubb, A. O. (1976) Biochim. Biophys. Acta 439, 82-94). In the present work, the major low and high molecular weight forms of the protein were isolated from plasma by immunosorption followed by gel chromatography. The plasma low molecular weight protein HC and the urinary protein had similar, if not identical, molecular weight, amino acid composition, NH2-terminal and carboxyl-terminal amino acid sequences and electrophoretic mobility. The low molecular weight plasma protein HC carried a yellow chromophore like the urinary protein, but its molar extinction coefficient at 280 nm was lower and its charge heterogeneity less pronounced than that of urinary protein HC. The plasma high molecular weight protein HC had a hydrodynamic volume which was greater than that of monomeric IgA but smaller than that of dimeric IgA. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the isolated high molecular weight protein followed by electrophoretic blotting and immunochemical analysis demonstrated that the protein contained four polypeptide chains: two light immunoglobulin chains (Mr = 23,000), one IgA alpha-chain (Mr = 54,000), and one chain with Mr approximately 90,000 which carried both alpha-chain and protein HC antigenic determinants. Whether the protein HC X IgA complex is a functionally significant part of the humoral immune system cannot be decided without further experimentation, but the complex was found to be completely absent from the blood plasma of patients with a selective deficiency of IgA-secreting immunocytes. The isolated low and high molecular weight plasma protein HC components were used as standard proteins in the construction of a quantitative crossed immunoelectrophoretic assay for the simultaneous quantitation of the two major protein HC components in blood plasma. The plasma concentrations of the low and high molecular weight protein HC components were measured by this method in 13 healthy Caucasians. The results for the low molecular weight protein HC were: mean, 20.3 mg/liter, S.D., 3.2 mg/liter, range, 13.6-26.0 mg/liter; and for the protein HC X IgA complex: mean, 293 mg/liter, S.D., 176 mg/liter, range, 36-620 mg/liter.</p>}},
  author       = {{Grubb, A O and López, C and Tejler, L and Mendez, E}},
  issn         = {{0021-9258}},
  keywords     = {{Adult; Alpha-Globulins/isolation & purification; Amino Acids/analysis; Carbohydrates/analysis; Cyanogen Bromide; Electrophoresis, Agar Gel; Humans; Immunodiffusion; Immunoelectrophoresis, Two-Dimensional; Immunoglobulin A/metabolism; Molecular Weight}},
  language     = {{eng}},
  number       = {{23}},
  pages        = {{707--14698}},
  publisher    = {{American Society for Biochemistry and Molecular Biology}},
  series       = {{The Journal of biological chemistry}},
  title        = {{Isolation of human complex-forming glycoprotein, heterogeneous in charge (protein HC), and its IgA complex from plasma. Physiochemical and immunochemical properties, normal plasma concentration}},
  url          = {{http://dx.doi.org/10.1016/S0021-9258(17)43919-6}},
  doi          = {{10.1016/S0021-9258(17)43919-6}},
  volume       = {{258}},
  year         = {{1983}},
}