Chemical and physicochemical studies of the component polypeptide chains of rabbit secretory immunoglobulin A

O'Daly, José A.; Cebra, John J.

doi:10.1021/bi00797a007

Cited by 76 publications

(34 citation statements)

References 21 publications

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“…The present observations would also be consistent with the reports (3,13) ever, because accurate data on the molecular weight of the J chain are not available, together with other technical difficulties such as variation in the uptake of stain by the different chains present in Ig.I\ and the presence of bound albumin which, after reduction, migrates in the J-chain region (Tomasi, unl)ublished observations), these results are at most, rough approximations. Assuming that 1gM1 contains a single J chain, it may be that during intracellular synthesis, J chain initially links two subunits in IgM and IgA and the remaining subunits in the higher polymers in both systems are bonded first noncovalently and subsequently by disulfide linkages.…”

Section: Resultssupporting

confidence: 90%

“…The IgIM was reduced according to Morris and Inman (7) at a protein concentration of 5 mg/ml, with 10-25 mM mercaptoethylamine for 1 hr at 300, followed by alkylation with [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] A partial specific volume of 0.717 was assumed in accordance with previously reported values for IgM (11).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Production of a Noncovalently Bonded Pentamer of Immunoglobulin M: Relationship to J Chain

1973

Proc. Natl. Acad. Sci. U.S.A.

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Human immunoglobulin M was reduced with concentrations of 2-mercaptoethylamine chosen so that approximately 40% of the immunoglobulin M was reduced to 7S subunits. Under these conditions, which selectively cleave intersubunit disulfides, J chain was released. The 7S subunits of immunoglobulin M so produced did not contain J chain. The high-molecular-weight immunoglobulin M remaining after treatment with 2-mercaptoethylamine had a sedimentation coefficient of 18.0 S and molecular weight of 1 million, and dissociated in 4 M guanidine into subunits similar in size to the 7S subunits. J chain was found in the 18.OS, noncovalently linked immunoglobulin M from which it was released only after more complete reduction with 10 mM dithiothreitol. The results are consistent with the hypothesis that J chain participates in the formation of the intersubunit linkages. However, it need not necessarily be directly involved in all of the intersubunit disulfides. It may play an important role in modulating the assembly of immunoglobulin M subunits, perhaps by inducing conformational changes that lead to noncovalent interactions between the subunits.Immunoglobulin M (IgM) has been shown to contain five subunits which are linked in a circular l)entamer. The IgM molecule does not dissociate in solvents such as guanidine, urea, or acid, which inhibit secondary (noncovalent) forces, but upon treatment with mild reducing conditions, the 19S molecule is cleaved into five subunits each with a sedimentation coefficient of approximately 7 S. The above observation suggests that the subunits are disulfide bonded in the intact molecule and that once these linkages are cleaved, the subunits do not possess secondary bonds of sufficient force to hold them together during sedimentation analysis.Halpern and Koshland (1) have recently described a new polypeptide chain (J chain) in rabbit secretory IgA. This chain is also present in other polymeric immunoglobulin molecules, such as IgM (2) and polymeric serum IgA of several species (3, 4). The function of J chain is unknown, but because it has been found only in polymeric immunoglobulin molecules, it has been postulated to be involved in the intersubunit linkage. Attempts at reaggregation of the reduced IgM molecule in the presence and absence of J chain have led to conflicting results regarding the requirement for J chain in the polymerization reaction (5, 6).This study examines the role of J chain in polymer formation in the IgM system. A unique noncovalently bonded 18S IgM molecule is described which contains J chain. It is produced by reduction with low concentrations of 2-mercaptoethylamine. The results are consistent with the hypothesis that although the J chain participates in the formation of the intersubunit linkages, it need not necessarily be involved directly in all of the intersubunit disulfide bonds. J chain may also serve to modulate the assembly of the IgM subunits (IgM'). MATERIALS AND METHODSFour human IgM\'s were isolated from the serum of patients with Waldenstr6m's macro...

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Section: Resultssupporting

confidence: 90%

Section: Methodsmentioning

confidence: 99%

Production of a Noncovalently Bonded Pentamer of Immunoglobulin M: Relationship to J Chain

1973

Proc. Natl. Acad. Sci. U.S.A.

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“…molecule^1 2 » 13 ] few data to support this assumption are reported. Less than one J chain of 15000 molecular weight was recovered per molecule of rabbit 1 IS IgAt 9 Both sieving methods, gel filtration on Sephadex G-200 and SDS acrylamide gel electrophoresis, yielded higher molecular weight values than revealed by ultracentrifugal studies. Several suggestions to explain this discrepancy have been put forward 1 9 » 10 J. Carbohydrate content may be the cause of anomalous behavior in gel filtrationt 14â nd SDS acrylamide gel electrophoresis^1 5 !.…”

Section: Resultsmentioning

confidence: 89%

The Molecular Weight of J Chains of Human IgM

Kownatzki¹,

Bähr²

1974

Biological Chemistry

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The molecular weight of J chains from a Waldenström macroglobulin was determined by equilibrium ultracentrifugation in Tris-NaCl buffer pH 8.0 and in OM guanidine x HC1. A value of 14400 in the dissociating system confirmed the findings of other authors. A molecular weight of 31000 in the non-dissociating buffer suggested that J chains in their natural environment exist as a double chain. Das Molekulargewicht der J-Komponente menschlicher IgM-Inwiunglobuline

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“…One of these is secretory component, which is a glycoprotein that occurs in colostrum and milk both bound to IgA and in free solution; when bound, it may or may not be held by disulphide bonds. It has a molecular weight of about 60000 in rabbit colostrum (355) and of about 46 000 in bovine colostrum (79); it has been shown (79) to be identical to the glycoprotein-a previously isolated from milk (185). The other component of IgA is the F component of molecular weight 15000, whose origin is uncertain (355).…”

Section: Primary Structurementioning

confidence: 98%

Section C. Chemistry of milk proteins

Lyster¹

1972

Journal of Dairy Research

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Chemical and physicochemical studies of the component polypeptide chains of rabbit secretory immunoglobulin A

Abstract: 1 WHO meeting on the Nomenclature of Immunoglobulins §terzl and Riha (1970).

Cited by 76 publications

References 21 publications

Production of a Noncovalently Bonded Pentamer of Immunoglobulin M: Relationship to J Chain

Production of a Noncovalently Bonded Pentamer of Immunoglobulin M: Relationship to J Chain

The Molecular Weight of J Chains of Human IgM

Section C. Chemistry of milk proteins

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