title: Fibrinogen and the early stages of polymerization to fibrin as studied by dynamic laser light scattering.
abstract: Human fibrinogen and the polymerization of fibrin after activation by the enzymes, thrombin and Batroxobin, were studied by means of dynamic laser light scattering (DLS). The apparent diffusion constant, D, for fibrinogen was measured and has a value of (1.80 +/- 0.42) X 10(-7) cm2 X s-1. D was found to contain contributions from the translational diffusion constant (Dt) as well as from the rotational diffusion constant (Dr). A comparison between experimental and calculated values of Dr and Dt suggests that fibrinogen in the absence of added Ca2+ expresses a certain degree of flexibility, while it is straightened in the presence of added Ca2+. The time dependence of D showed periodic oscillations, while the average D values decreased with time. Thrombin and Batroxobin caused similar behaviour of D. The period length was related to the enzyme concentration, clotting time (Ct) and the rate of release of fibrinopeptide A (FPA). No periodic oscillations were observed in experiments where the enzyme was replaced by saline, or in experiments using a dysfunctional fibrinogen (fibrinogen Aarhus) which displayed slow rates of FPA-release and polymerization. We propose that the periodic oscillations in a system far from equilibrium may be explained by conformational changes occurring in the fibrinogen molecule during enzyme activation and polymerization.
mesh_terms: D012103:Batroxobin / Q000494:pharmacology; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004058:Diffusion; D005337:Fibrin / Q000378:metabolism*; D005340:Fibrinogen / Q000378:metabolism*; D005344:Fibrinopeptide A / Q000378:metabolism; D005345:Fibrinopeptide B / Q000378:metabolism; D006801:Humans; D007834:Lasers; D011108:Polymers; D012542:Scattering, Radiation; D013917:Thrombin / Q000494:pharmacology
chemical_list: D011108:Polymers; D005344:Fibrinopeptide A; D005345:Fibrinopeptide B; D005337:Fibrin; D005340:Fibrinogen; D012103:Batroxobin; D013917:Thrombin