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Biomedical subjects

A Feinstein

Publications and source records attributed to A Feinstein.

At least 145 records · Page 8Linked to original sources
PubMed1975

Interchain disulphide bridges of mouse immunoglobulin M.

Mouse IgM (immunoglobulin M) was selectively and partially reduced and treated with iodo[2-14C]acetate to label the interchain disulphide bridges. The carboxymethylation was studied in some detail. The labelled peptides were purified, sequenced and positioned by homology with human IgM. Only peptides originating from three interchain disulphide bridges were labelled, in contrast with the four labelled bridges obtained in human IgM under the same conditions. These peptides are homologous to human bridge peptides forming the heavy-light bridge and two inter-heavy bridges, one present in the CMU2 region and the other in the C-terminal region. The inter-heavy bridge in the Cmu2 region was alone cleaved and radioactively labelled in selectively reduced IgM held together as a pentamer by non-covalen interactions. The same bridge was the only one to be totally cleaved in subunits released after more extensive, though still selective, reduction. In the light of these results a possible arrangement of the disulphide bridges of the mouse IgM.

Alkylation↗
PubMed1973

Structural studies on individual components of bovine transferrin.

The single-banding components of bovine transferrin from animals homozygous for the four transferrin variants found in the U.K. were isolated. Sedimentation equilibrium ultracentrifugation and sodium dodecyl sulphate-polyacrylamide-gel electrophoresis showed that the bands of a single variant have molecular weights of 77500 and 73300 respectively. The different bands of a single variant and single bands of different variants show no evidence of size heterogeneity or of low-molecular-weight peptides being split off after reduction in 6m-guanidine hydrochloride. The two slower bands of a single variant, which both contain 2 molecules of sialic acid/molecule of protein, have the same molecular weight and amino acid composition, and give identical peptide ;maps', although differences in composition and peptide ;maps' occur between the different variants. The results support the concept that bovine transferrin is essentially a single polypeptide chain, but they do not explain differences in electrophoretic mobility between bands of the same variant which are not produced by differing sialic acid content.

Amino Acids↗