Biomaterial Database

Binding of secretory component to human immunoglobulin M. 1976

E Lindh, and I Björk

The binding of human free secretory component to immoglobulin M (IgM) has been studied in vitro as a model for the formation of complexes between the two proteins in vivo. Three IgM myelomas and normal serum IgM were found to bind secretory component in amounts from 0.8 to 2.0 mol per mol of IgM. This variation in binding was not related to a corresponding variation of the J-chain content of the immunoglobulins, but more likely it was due to varying amounts of unspecifically bound serum proteins blocking the attachment of secretory component. In contrast to complexes with immunoglobulin A (IgA), the binding of secretory component to IgM appeared to be solely of a noncovalent nature, as all secretory component was released from complexes with IgM during gel chromatography in 6 M guanidine hydrochloride. Studies with tryptic fragments of one of the IgM myelomas indicated that the binding site for secretory component is located on the (Fc)5mu part of the IgM pentamer. Finally, only minimal conformational changes were found to accompany complex formation between secretory component and IgM, analogous to what has earlier been reported for the attachment of the secretory component to IgA.

UI	MeSH Term	Description	Entries
D007071	Immunoglobulin A, Secretory	The principle immunoglobulin in exocrine secretions such as milk, respiratory and intestinal mucin, saliva and tears. The complete molecule (around 400 kD) is composed of two four-chain units of IMMUNOGLOBULIN A, one SECRETORY COMPONENT and one J chain (IMMUNOGLOBULIN J-CHAINS).	Colostral IgA,IgA, Exocrine,IgA, Secretory,SIgA,Secretory IgA,Secretory Immunoglobulin A,Exocrine IgA,IgA, Colostral
D007075	Immunoglobulin M	A class of immunoglobulin bearing mu chains (IMMUNOGLOBULIN MU-CHAINS). IgM can fix COMPLEMENT. The name comes from its high molecular weight and originally was called a macroglobulin.	Gamma Globulin, 19S,IgM,IgM Antibody,IgM1,IgM2,19S Gamma Globulin,Antibody, IgM
D007144	Immunoglobulin J-Chains	A 15 kDa "joining" peptide that forms one of the linkages between monomers of IMMUNOGLOBULIN A or IMMUNOGLOBULIN M in the formation of polymeric immunoglobulins. There is one J chain per one IgA dimer or one IgM pentamer. It is also involved in binding the polymeric immunoglobulins to POLYMERIC IMMUNOGLOBULIN RECEPTOR which is necessary for their transcytosis to the lumen. It is distinguished from the IMMUNOGLOBULIN JOINING REGION which is part of the IMMUNOGLOBULIN VARIABLE REGION of the immunoglobulin light and heavy chains.	Ig J Chains,J-Chains, Immunoglobulin,Ig J-Peptide,Immunoglobulin J Polypeptide,Immunoglobulin J-Peptide,Chains, Ig J,Ig J Peptide,Immunoglobulin J Chains,Immunoglobulin J Peptide,J Chains, Ig,J Chains, Immunoglobulin,J Polypeptide, Immunoglobulin,J-Peptide, Ig,J-Peptide, Immunoglobulin,Polypeptide, Immunoglobulin J
D009194	Myeloma Proteins	Abnormal immunoglobulins characteristic of MULTIPLE MYELOMA.	M Components,Proteins, Myeloma
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D002942	Circular Dichroism	A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Circular Dichroism, Vibrational,Dichroism, Circular,Vibrational Circular Dichroism
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D013056	Spectrophotometry, Ultraviolet	Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Ultraviolet Spectrophotometry