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Biomedical subjects

G M Edelman

Publications and source records attributed to G M Edelman.

At least 361 records · Page 20Linked to original sources
PubMed1970

A genetic marker in the variable region of light chains of mouse immunoglobulins.

A genetic variation was observed upon autoradiographic comparison of tryptic peptide maps of (14)C-labeled normal light chains from 17 different inbred strains of mice. The difference was found in strains AKR/J, C58/J, and RF/J. Chemical analyses showed that the differences were in a region of the amino acid sequence in the neighborhood of half-cystine I of the variable region of the light chain. Breeding experiments showed that the difference segregated in a classical Mendelian fashion.

Amino Acids↗
PubMed1969

Amino acid incorporation into rat brain proteins during spreading cortical depression.

Unilateral spreading cortical depression was elicited by applying potassium chloride solutions to the dura of conscious, freely moving rats. Incorporation of (3)H-leucine into soluble cortical proteins was decreased in the depressed hemisphere relative to the control side, while soluble brainstem proteins from both sides had the same specific activity. Various subfractions of soluble cortical proteins were affected to equal degrees.

Amino Acids↗
PubMed1969

Deoxyribonuclease IV: a new exonuclease from mammalian tissues.

An exonuclease which specifically degrades double-standard DNA has been isolated from rabbit tissues. The enzyme has an approximate molecular weight of 42,000, requires a divalent metal ion as cofactor, and attacks DNA at the 5'-terminal ends, thereby liberating 5'-mononucleotides. It degrades several synthetic polydeoxynucleotides of single repeating base sequences more rapidly than DNA from natural sources. The specificity of this mammalian enzyme resembles that of several microbial enzymes (phage lambda exonuclease and DNA polymerase) which appear to be required for repair and recombination of DNA.

Animals↗
PubMed1969

The covalent structure of an entire gammaG immunoglobulin molecule.

The complete amino acid sequence of a human gammaG1 immunoglobulin (Eu) has been determined and the arrangement of all of the disulfide bonds has been established. Comparison of the sequence with that of another myeloma protein (He) suggests that the variable regions of heavy and light chains are homologous and similar in length. The constant portion of the heavy chain contains three homology regions each of which is similar in size and homologous to the constant region of the light chain. Each variable region and each constant homology region contains one intrachain disulfide bond. The half-cystines participating in the interchain bonds are all clustered within a stretch of ten residues at the middle of the heavy chains.These data support the hypothesis that immunoglobulins evolved by gene duplication after early divergence of V genes, which specified antigen-binding functions, and C genes, which specified other functions of antibody molecules. Each polypeptide chain may therefore be specified by two genes, V and C, which are fused to form a single gene (translocation hypothesis). The internal homologies and symmetry of the molecule suggest that homology regions may have similar three-dimensional structures each consisting of a compact domain which contributes to at least one active site (domain hypothesis). Both hypotheses are in accord with the linear regional differential of function in antibody molecules.

Amino Acid Sequence↗
PubMed1969

Subgroups of amino acid sequences in the variable regions of immunoglobulin heavy chains.

The amino acid sequence of the first 133 residues of the heavy (gamma) chain from a human gammaG immunoglobulin (He) has been determined. This gamma-chain is identical in Gm type to that of protein Eu, the complete sequence of which has been reported. Comparison of the two sequences substantiates the previous suggestion that there are subgroups of variable regions of heavy chains. The variable region of Eu has been assigned to subgroup I and that of He to subgroup II; on the other hand, the constant regions of the two proteins appear to be identical. Comparison of the sequence of the heavy chain of He with the heavy chain sequences determined in other laboratories suggests that the variable region of subgroup II is at least 118 residues long. The nature and distribution of amino acid variations in this heavy chain subgroup resemble those observed in light chain subgroups. These studies provide evidence that the translocation hypothesis applies to heavy as well as to light chains, viz., genes for variable regions (V) are somatically translocated to genes for constant regions (C) to form complete VC structural genes.

Amino Acid Sequence↗
PubMed1968

Phylogenetic origins of antibody structure. 3. Antibodies in the primary immune response of the sea lamprey, Petromyzon marinus.

The sea lamprey, Petromyzon marinus, has been found to produce specific antibodies after immunization with bacteriophage f2. Antibody activity is localized in 6.6S and 14S fractions of lamprey serum. The 6.6S antibodies were purified by a combination of zone electrophoresis, ion exchange chromatography, and gel filtration. Antigenic analysis of the 6.6S antibodies showed them to be free of other serum proteins and antigenically similar or identical to the 14S fraction. Evidence has been obtained which suggests that the 6.6S immunoglobulins consist of light components (molecular weight 25,000) and heavy components (molecular weight 70,000). In the immunoglobulin, these polypeptides appear to be linked via weak interactions but not by interchain disulfide bonds. Molecular weight analyses support the view that the chains can undergo concentration-dependent dissociation in aqueous solutions. Amino acid analyses showed that the compositions of the light and heavy components were similar and that aspartic acid or asparagine was the predominant amino terminal residue. Starch gel electrophoresis indicated that the subunits of lamprey antibodies are diffusely heterogeneous. The heavy chain mobility corresponded to that of micro-chains and resembled that of heavy chains of shark and sting ray immunoglobulins. In the course of the fractionation a 46S natural hemagglutinin composed of lower molecular weight subunits was isolated. This hemagglutinin did not resemble the lamprey immunoglobulin although it had a similar zone electrophoretic mobility in the beta-region. These studies are consistent with the hypothesis that micro-chains were the earliest of the heavy chain classes to emerge and further support the view that the multichain structure of immunoglobulins is a fundamental feature of antibody molecules.

Animals↗