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Biomedical subjects

J D Capra

Publications and source records attributed to J D Capra.

At least 289 records · Page 16Linked to original sources
PubMed1971

Localization of two additional hypervariable regions in immunoglobulin heavy chains.

Cyanogen bromide fragments were isolated from the heavy chains of three human IgG myeloma proteins of the V(H)III subgroup, sequenced by an automated method, and localized to the variable region. Inspection of these sequences, together with corresponding stretches from both human and animal proteins (studied in other laboratories) led to the detection of two additional hypervariable regions characteristic of the V(H) segment of immunoglobulin heavy chains. These areas of hypervariability, involving heavy-chain residues 86-91 and 101-109, were separated by a region of relative constancy. The close relationship of these two hypervariable regions, and the previously described first heavy-chain hypervariable region (residues 31-37), to the first heavy-chain disulphide bridge implies that the three hypervariable areas might be in close steric approximation in native immunoglobulin molecules. Examination of the sequences of the terminal portion of V(H) of all these proteins (the segment from residue 95 to the beginning of homology region C(H)l) revealed that no subgroup-specific residues could be identified in this area. Thus, heavy-chain subgroup distinctions may not extend through the entire variable region.

Amino Acid Sequence↗
PubMed1970

Amino acid sequence similarities in two human anti gamma globulin antibodies.

Certain individuals with hypergammaglobulinemic purpura contain in their serum anti gamma globulins of restricted heterogeneity. These antibodies, characteristically of the gammaG type, were isolated from two unrelated individuals and their light polypeptide chains were subjected to amino acid sequence analysis. Although these anti gamma globulin antibodies conform to the basic VK(1) sequence, substitutions not previously encountered were found in five positions. The two antibodies were identical with each other up to residue 40 from the N-terminus of the light chains.

Amino Acid Sequence↗
PubMed1970

Aggregation of gamma-G3 proteins: relevance to the hyperviscosity syndrome.

Studies on the sera and isolated proteins from 14 patients with gammaG3 multiple myeloma revealed a concentration- and temperature-dependent aggregation which was not encountered in 26 sera from patients with multiple myeloma involving other gammaG subgroups. When the gammaG3 myeloma sera were diluted and characterized by analytical ultracentrifugation, complex formation was minimal. However, when these sera were examined undiluted, marked complex formation was observed. Studies on the isolated proteins, their enzymatic fragments, as well as their heavy and light polypeptide chains localized the aggregating sites to the Fd fragment of the heavy chains. The findings were also documented by acrylamide-gel electrophoresis and capillary tube viscometry.THE HYPERVISCOSITY SYNDROME WAS OBSERVED IN SIX PATIENTS: three with gammaG3 myeloma and three with gammaG1 myeloma. In the latter group extreme protein concentrations appeared essential for the development of the clinical symptoms. The gammaG3 cases, however, because of the aggregation phenomenon, showed the syndrome at relatively low protein concentrations.

Bence Jones Protein↗