Molecular weight analysis of antithrombin III-heparin and antithrombin III-thrombin-heparin complexes.
Year: 1986
Type: article
Abstract: The molecular interactions between components of the heparin-catalyzed antithrombin III/thrombin reaction were investigated by light scattering. When heparin was added to antithrombin III, the molecular weight increased to a maximum and then decreased to that of a 1:1 (antithrombin III X heparin) complex. The initial molecular weights at low heparin to antithrombin III ratios were consistent with the formation of a 2:1 (antithrombin III X heparin) complex in which only one antithrombin III molecule had undergone the conformational change measured by protein fluorescence enhancement. The peak molecular weight never reached that of a complete 2:1 complex. This behavior was observed for bovine and human antithrombin III in the presence of both unfractionated heparin and high molecular weight-high affinity heparin. Pentosane polysulfate also caused some multiple associations. Bovine antithrombin III and thrombin formed a 1:1 complex that underwent further aggregation within minutes, while the human proteins did not aggregate on this time scale after forming the 1:1 complex. In the presence of stoichiometric amounts of heparin, the bovine proteins formed an initial complex of Mr = 230,000 (corresponding to a dimer of heparin-antithrombin III-thrombin) which underwent further aggregation. The human proteins, however, formed a 1:1 (antithrombin III X thrombin) initial complex in the presence of heparin, followed by aggregation. These interactions of thrombin and antithrombin with heparin suggest complex interactions that could relate to heparin function.
Source: Journal of Biological Chemistry
Authors: C H Pletcher, M T Cunningham, G L Nelsestuen
Language: English
Subfield: Hematology
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
Awards: G3054066612, G3070493499
OpenAlex ID: W1560933109