Structure of alpha-polymer from in vitro and in vivo highly cross-linked human fibrin

• Published in: The Journal of biological chemistry Vol. 253; no. 18; pp. 6614 - 6622
• Main Authors: Fretto, L J, McKee, P A
• Format: Journal Article
• Language: English
• Published: United States American Society for Biochemistry and Molecular Biology 25-09-1978
• Subjects: Amino Acids - analysis; Cyanogen Bromide; Fibrin; Fibrinolysin; Humans; Macromolecular Substances; Peptide Fragments - analysis
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(19)46975-5

Peptides derived from plasmic and cyanogen bromide (CNBr) cleavage of highly cross-linked fibrin were isolated and characterized
by sodium dodecyl sulfate-gel electrophoresis, amino acid analyses, cyanoethylation, and NH2-terminal analyses. Extended plasmic
digestions of human fibrin containing four epsilon-(gamma-glutamyl)lysine cross-links per molecule produced a peptide of alpha-chain
origin (Mr congruent to 21,000) which was comprised of a small donor peptide cross-linked to the acceptor site peptide from
the middle of the alpha-chain. CNBr cleavage of highly cross-linked in vitro fibrin or of fibrin from a spontaneously formed
in vivo arterial embolus produced about three cross-linked species of molecular weights 30,000 to 40,000, each of which contained
the largest CNBr fragment (Mr = 29,000) from the alpha-chain. The predominant cross-link-containing CNBr fragments derived
their donor group from the near COOH-terminal region of the alpha-chain as judged by difference amino acid compositions and
NH2-terminal analyses. Additionally, cross-linked fragments of molecular weights 68,000 to 70,000 which appeared to contain
two acceptor site peptides (Mr = 29,000) were detected in minor amounts in the CNBr digests of fibrin formed from whole plasma
or from purified, plasminogen-free fibrinogen. No larger polymeric cross-linked CNBr fragment was generated from any of the
highly cross-linked fibrin preparations examined. A model for the predominant mode of alpha-chain polymerization is proposed.