RESUMEN
IgA1 populations were reduced over a range of dithiothreitol concentrations and the products were examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis and peptide mapping. The study showed that IgA was more resistant to reduction than other immunoglobulin classes (IgG, IgM). SDS-polyacrylamide gel electrophoresis showed that intersubunit bond and H-L bond were the most labile disulfide in polymeric and monomeric IgA, respectively. Peptide mapping revealed that the itrachain disulfide of the C alpha 2 domain was more or equally sensitive to the reduction than H-L and intersubunit bonds. Electrochemical experiments demonstrated that this bond had redox properties and the possibility involving disulfide exchange is discussed.
Asunto(s)
Inmunoglobulina A , Regiones Constantes de Inmunoglobulina , Inmunoglobulinas , Fenómenos Químicos , Química , Disulfuros , Ditiotreitol , Humanos , Fragmentos de Inmunoglobulinas , Cadenas Pesadas de Inmunoglobulina , Cadenas Ligeras de Inmunoglobulina , Oxidación-ReducciónRESUMEN
The cysteinyl peptides of monomeric and polymeric IgA were studied by comparative autoradiography. Autoradiographies of polymeric IgA (containing or lacking J chain) showed an extra cysteinyl peptide which was never found in the monomeric forms. A similar peptide was obtained when reduced IgA was cleaved by BrCN. The possible identity of this fragment is discussed.
Asunto(s)
Cisteína , Inmunoglobulina A , Fragmentos de Inmunoglobulinas , Humanos , Sustancias Macromoleculares , Fragmentos de Péptidos/análisisRESUMEN
We report herein a new case of C2 deficiency in a patient with systemic lupus. The subject and one of her brothers, who shows no clinical manifestations, are hymozygous C2 deficient. All other family members are heterozygous for the C2 deficiency. Gene for C2 deficiency (C2d) was shown to be inherited with HLA-A9, B7/Bfs and HLA-A10, B27/Bfs haplotypes. This association has not previously been described.