title: The conversion of fibrinogen to fibrin: recombinant fibrinogen typifies plasma fibrinogen.
abstract: Plasma fibrinogen is a mixture of multiple molecular forms arising mainly through alternative mRNA processing and subsequent posttranslational modification. Recombinant fibrinogen is synthesized without alternative mRNA processing in a cultured cell system that may generate novel posttranslational modifications. Thus, to show that recombinant fibrinogen can serve as a functional model for plasma fibrinogen, we have examined the conversion of fibrinogen to fibrin, comparing the recombinant with the plasma protein. We examined the kinetics of (1) thrombin-catalyzed fibrinopeptide release, (2) thrombin-catalyzed polymerization of fibrinogen, (3) the polymerization of fibrin monomers, and (4) FXIIIa-catalyzed cross-link formation. We saw small differences in polymerization, suggesting that the ordered assembly of protofibrils and fibers was not identical. In all other analyses, we found that plasma fibrinogen and recombinant fibrinogen were remarkably similar. Using electron microscopy, we examined the structures of individual fibrinogen molecules and fibrin clots. Individual fibrinogen molecules were predominantly three nodule structures for both recombinant and plasma proteins. Both samples also displayed four nodule structures, but fewer four nodule structures were found with recombinant fibrinogen. Fibrin clot structures were essentially indistinguishable. We concluded that recombinant fibrinogen can serve as a accurate model for plasma fibrinogen.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill 27599-7525, USA.
authors.forename: O V
authors.initials: OV
authors.lastname: Gorkun
authors.forename: Y I
authors.initials: YI
authors.lastname: Veklich
authors.forename: J W
authors.initials: JW
authors.lastname: Weisel
authors.forename: S T
authors.initials: ST
authors.lastname: Lord
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D001777:Blood Coagulation; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D003553:Cystine / Q000378:metabolism; D000939:Epitopes / Q000737:chemistry / Q000276:immunology; D005337:Fibrin / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D005338:Fibrin Fibrinogen Degradation Products / Q000276:immunology; D005340:Fibrinogen / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005344:Fibrinopeptide A / Q000378:metabolism; D005345:Fibrinopeptide B / Q000378:metabolism; D006801:Humans; D008855:Microscopy, Electron, Scanning; D011487:Protein Conformation; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism*; D013917:Thrombin / Q000378:metabolism; D011503:Transglutaminases / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D005338:Fibrin Fibrinogen Degradation Products; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D005344:Fibrinopeptide A; D005345:Fibrinopeptide B; D003553:Cystine; D005337:Fibrin; D005340:Fibrinogen; D011503:Transglutaminases; D013917:Thrombin