Intramolecular Localization of the Acceptor Cross-Linking Sites in Fibrin

Using 1-(14)C-glycine ethyl ester to titrate and label the acceptor cross-linking sites in fibrin, it was possible to localize and characterize the reactivity of these sites. In terms of sulfitolyzed chain fragments, both alpha and gamma chains were shown to act as amine-acceptors, the site in gamma being more reactive. Identification and isolation of the acceptor loci were also achieved after cyanogen bromide fragmentation. It is interesting that the "N-terminal disulfide knot" portion of fibrin does not seem to contain acceptor functions.