The overall objective of the proposed reserach is to elucidate the mechanism whereby heparin and related glycosaminoglycans interact with circulating proteins that promote or suppress blood coagulation. The specific focus of our investigations will be on the interaction of antithrombin with thrombin and coagulation- factor Xa, and the actions of heparin on these processes. One aspect of the work, therefore, will be on the structural characteristics of heparin and analogous compounds, and the relation of their specific chemical structure with biological activity. The other facet will be on structure of antithrombin as it relates to its interaction with the procoagulants and with heparin. Detailed investigations will be performed on specific fractions on heparins and heparan sulfates from different animal and tissue sources with the purpose of defining the location of certain units or sequences within its polymeric chain. Our approach will utilize novel procedures involving the structural characterization of the glycosaminoglycans in their native proteglycan form, while they are linked to specified insoluble matrices. Heparin segments defined in terms of chemical properties and location within the chain, will be characterized with respect to the effect on coagulation process and other biological activities. The studies on the structure of antithrombin will deal mainly with delineating the sites and polypeptide segment(s) that interact with thrombin, factor Xa and heparin. For this purpose we will utilize well-defined fragments of antithrombin obtained after chemical and enzymatic degradations. Heparin is of considerable interest because of its high anticoagulant potency and its clinical use in the treatment and prevention of thromboses. Moreover, since heparin appears to mimic certain glycosaminoglycans of endothelial cells, elucidation of its mechanism of action should clarify some of the physiologic factors that control or modulate coagulation processes.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL016955-17
Application #
3335305
Study Section
Hematology Subcommittee 2 (HEM)
Project Start
1977-05-01
Project End
1992-04-30
Budget Start
1990-05-01
Budget End
1991-04-30
Support Year
17
Fiscal Year
1990
Total Cost
Indirect Cost
Name
New York Medical College
Department
Type
Schools of Medicine
DUNS #
City
Valhalla
State
NY
Country
United States
Zip Code
10595
Leong, J M; Robbins, D; Rosenfeld, L et al. (1998) Structural requirements for glycosaminoglycan recognition by the Lyme disease spirochete, Borrelia burgdorferi. Infect Immun 66:6045-8
Lahiri, B; Lai, P S; Pousada, M et al. (1992) Depolymerization of heparin by complexed ferrous ions. Arch Biochem Biophys 293:54-60
Jaikaria, N S; Rosenfeld, L; Khan, M Y et al. (1991) Interaction of fibronectin with heparin in model extracellular matrices: role of arginine residues and sulfate groups. Biochemistry 30:1538-44
Danishefsky, I; Rosenfeld, L; Kuhn, L et al. (1989) Location of specific units in heparin and heparan sulfate. Ann N Y Acad Sci 556:29-35
Rosenfeld, L; Danishefsky, I (1988) Location of specific oligosaccharides in heparin in terms of their distance from the protein linkage region in the native proteoglycan. J Biol Chem 263:262-6
Rosenfeld, L; Danishefsky, I (1986) A fragment of antithrombin that binds both heparin and thrombin. Biochem J 237:639-46
Agarwal, A; Danishefsky, I (1986) Requirement of free carboxyl groups for the anticoagulant activity of heparin. Thromb Res 42:673-80
Radoff, S; Danishefsky, I (1985) Distribution of glucuronic and iduronic acid units in heparin chains. J Biol Chem 260:15106-11
Rosenfeld, L; Radoff, S; Danishefsky, I (1985) The uronic acid composition of anticoagulantly active and inactive heparin. Arch Biochem Biophys 242:574-8