Search PubMed⌕ Search

Biomedical subjects

R Chen

Publications and source records attributed to R Chen.

At least 613 records · Page 34Linked to original sources
PubMed1970

Isolation, characterization, and location of a donor-acceptor unit from cross-linked fibrin.

The cross-linking systems of bovine and human fibrins were studied by the introduction of a radioactive substitute donor as an inhibitor of fibrin cross-linking, separation of the constituent polypeptide chains after sulfitolysis, and tryptic digestion of the labeled gamma-chains. The information gathered from this approach enabled us to isolate and characterize the complete donor-acceptor unit in tryptic digests of fibrin gamma-gamma cross-linked systems. In both bovine and human fibrin, this kind of cross-linking is accomplished by reciprocal bridging between overlapping carboxy-terminal segments of neighboring gamma-chains. The amino acid sequence of the carboxy-terminal heptadecapeptide of the bovine gamma-chain was determined and an alignment of the corresponding region of the human gamma-chain established.

Amino Acid Sequence↗
PubMed1969

Identification of the polypeptide chains involved in the cross-linking of fibrin.

The stabilization of fibrin clots by activated factor XIII involves two different sets of cross-linked chains. In one case (type I) two gamma-chains are linked to each other, indicating that gamma-chains have both donor (suitable lysyl-) and acceptor (suitable glutaminyl-) functions. A second system (type II) consists of a gamma-chain linked to an alpha-chain. Experiments with a substitute donor (glycine ethylester) indicate that only gamma-chains have enzyme-accessible acceptor sites, suggesting that alpha-chain participation is limited to lysyl side chains. A model molecular arrangement for fibrin has been suggested which accommodates all the data.

Amino Acids↗