Biomaterial Database

Disulfide bonding of secretory component to a single monomer subunit in human secretory IgA. 1977

B J Underdown, and J De Rose, and A Plaut

The arrangement of disulfide bonds joining secretory component (SC) to the alpha chains in secretory IgA was studied by determining the molecular size of the principal fragments resulting from CNBr digestion of secretory dimeric Fc fragments from IgA (Fc)2alpha fragments). In vitro complexes formed by incubating 125I-free SC and myeloma 131I-(Fc)2alpha fragments were isolated by gel filtration and subsequently digested with cyanogen bromide. The CNBr digests of SC-(Fc)2alpha fragments were analyzed by gel filtration in 5 M guanidine. Two principal fragments were obtained, one containing a monomeric Fc fragment from IgA (Fcalpha) associated with SC (m.w. congruent to 110,000) and a second containing the second Fcalpha monomer (m.w. congruent to 50,000) from the dimeric SC-(Fc)2alpha. Similar results were obtained when secretory (Fc)2alpha fragments isolated from native secretory IgA dimer were subjected to CNBr digestion. The data indicate that SC is disulfide bonded to a single monomer subunit in secretory IgA dimer.

UI	MeSH Term	Description	Entries
D007070	Immunoglobulin A	Represents 15-20% of the human serum immunoglobulins, mostly as the 4-chain polymer in humans or dimer in other mammals. Secretory IgA (IMMUNOGLOBULIN A, SECRETORY) is the main immunoglobulin in secretions.	IgA,IgA Antibody,IgA1,IgA2,Antibody, IgA
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
D007128	Immunoglobulin Fragments	Partial immunoglobulin molecules resulting from selective cleavage by proteolytic enzymes or generated through PROTEIN ENGINEERING techniques.	Antibody Fragment,Antibody Fragments,Ig Fragment,Ig Fragments,Immunoglobulin Fragment,Fragment, Antibody,Fragment, Ig,Fragment, Immunoglobulin,Fragments, Antibody,Fragments, Ig,Fragments, Immunoglobulin
D007137	Immunoglobulin alpha-Chains	The class of heavy chains found in IMMUNOGLOBULIN A. They have a molecular weight of approximately 58 kDa and contain about 470 amino acid residues arranged in four domains and an oligosaccharide component bound covalently to their Fc fragment constant region.	Ig alpha Chains,Immunoglobulins, alpha-Chain,Immunoglobulin alpha-Chain,alpha-Chain Immunoglobulins,alpha-Immunoglobulin Heavy Chain,alpha-Immunoglobulin Heavy Chains,Chains, Ig alpha,Heavy Chain, alpha-Immunoglobulin,Heavy Chains, alpha-Immunoglobulin,Immunoglobulin alpha Chain,Immunoglobulin alpha Chains,Immunoglobulins, alpha Chain,alpha Chain Immunoglobulins,alpha Chains, Ig,alpha Immunoglobulin Heavy Chain,alpha Immunoglobulin Heavy Chains,alpha-Chain, Immunoglobulin,alpha-Chains, Immunoglobulin
D007141	Immunoglobulin Fc Fragments	Crystallizable fragments composed of the carboxy-terminal halves of both IMMUNOGLOBULIN HEAVY CHAINS linked to each other by disulfide bonds. Fc fragments contain the carboxy-terminal parts of the heavy chain constant regions that are responsible for the effector functions of an immunoglobulin (COMPLEMENT fixation, binding to the cell membrane via FC RECEPTORS, and placental transport). This fragment can be obtained by digestion of immunoglobulins with the proteolytic enzyme PAPAIN.	Fc Fragment,Fc Fragments,Fc Immunoglobulin,Fc Immunoglobulins,Ig Fc Fragments,Immunoglobulin Fc Fragment,Immunoglobulins, Fc,Immunoglobulins, Fc Fragment,Fc Fragment Immunoglobulins,Fc Fragment, Immunoglobulin,Fc Fragments, Ig,Fc Fragments, Immunoglobulin,Fragment Immunoglobulins, Fc,Fragment, Fc,Fragments, Ig Fc,Immunoglobulin, Fc
D007143	Immunoglobulin Heavy Chains	The largest of polypeptide chains comprising immunoglobulins. They contain 450 to 600 amino acid residues per chain, and have molecular weights of 51-72 kDa.	Immunoglobulins, Heavy-Chain,Heavy-Chain Immunoglobulins,Ig Heavy Chains,Immunoglobulin Heavy Chain,Immunoglobulin Heavy Chain Subgroup VH-I,Immunoglobulin Heavy Chain Subgroup VH-III,Heavy Chain Immunoglobulins,Heavy Chain, Immunoglobulin,Heavy Chains, Ig,Heavy Chains, Immunoglobulin,Immunoglobulin Heavy Chain Subgroup VH I,Immunoglobulin Heavy Chain Subgroup VH III,Immunoglobulins, Heavy Chain
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D010447	Peptide Hydrolases	Hydrolases that specifically cleave the peptide bonds found in PROTEINS and PEPTIDES. Examples of sub-subclasses for this group include EXOPEPTIDASES and ENDOPEPTIDASES.	Peptidase,Peptidases,Peptide Hydrolase,Protease,Proteases,Proteinase,Proteinases,Proteolytic Enzyme,Proteolytic Enzymes,Esteroproteases,Enzyme, Proteolytic,Hydrolase, Peptide
D002621	Chemistry	A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.
D003488	Cyanogen Bromide	Cyanogen bromide (CNBr). A compound used in molecular biology to digest some proteins and as a coupling reagent for phosphoroamidate or pyrophosphate internucleotide bonds in DNA duplexes.	Bromide, Cyanogen