The essential covalent structure of human fibrinogen evinced by analysis of derivatives formed during plasmic hydrolysis.

摘要: Abstract In an effort to determine the essential structural features of human fibrinogen, plasmic hydrolysis was carried out and degradation products were identified analyzed. agreement with previous work, initial attack shown occur in Aα chains release portions their COOH-terminal regions (designated /α terminology developed describe present findings), whereas simultaneous, but slower, occurs NH2-terminal region Bβ/ chains) results removal remnants containing peptide B. These changes, plus internal cleavages leading eventually separation Fragments D E (terminology Nussenzweig et al.), produce a series high molecular weight derivatives which can be separated by polyacrylamide gel electrophoresis unreduced samples sodium dodecyl sulfate. (These designated Bands II through VII order decreasing size; Band as Fragment X Marder al.) Upon further derivative lose portion one its Bβ (as remnant /β6, 32,000) form VIII (Fragment Y or, alternatively, undergo cleavage yield early forms D1 E1, respectively). Derivative VIII, turn, is degraded E1 later D. Once cleaved from parent molecule, these continue /β chains. degradative pathways lead (D1 D5) differ weight. Additional smaller fragment (E2) which, unlike lacks A. Immunochemical studies obtained at successive phases digestion demonstrated presence least five antigenic determinants on fibrinogen molecule. One located chains; another, E; three others, Of latter, associated /β6 second F) F, arise D; third D) that lost when F evolved. Electrophoretic behavior before after reduction revealed intrachain disulfide bridge each /α15 chain. Studies subunit composition recovery various indicated it dimeric structure substantial both γ /γ1 chains, having 42,000) hence only such (linked interchain bridges) generated results, those reported led conclusion itself has structure, "backbone" consists pair linked directly other bridging covalently (enter or indirectly) two