Dimeric ristocetin flocculates proteins, binds to platelets, and mediates von Willebrand factor-dependent agglutination of platelets. J Biol Chem 1991 May 05;266(13):8149-55
Date
05/05/1991Pubmed ID
2022635DOI
10.1016/s0021-9258(18)92954-6Scopus ID
2-s2.0-0025901142 (requires institutional sign-in at Scopus site) 132 CitationsAbstract
Ristocetin in aqueous solution dimerizes with an equilibrium dissociation constant of 5.0 x 10(-4) M, i.e. approximately 1.1 mg ml-1 (Waltho, J.P., and Williams, D. H. (1989) J. Am. Chem. Soc. 111, 2475-2480). At concentrations of about 1.0 mg ml-1 ristocetin flocculates many proteins, lyses platelets and, in the presence of von Willebrand factor, agglutinates both fresh and formalin-fixed platelets. Because ristocetin exists as both monomeric and dimeric species, we sought to determine which of these forms flocculates proteins and agglutinates platelets. We found that: 1) the initial rate of flocculation of certain proteins, 2) the initial rate of agglutination of formalin-fixed platelets, and 3) the binding of ristocetin to formalin-fixed platelets are higher order solely with respect to the concentration of ristocetin dimers. As to the operative mechanism, it appears that bifunctional dimers cross-link proteins that possess multiple copies of a common recognition site. Preliminary evidence indicates that a recognition site is a beta-turn of the form X-P-G-X'.
Author List
Scott JP, Montgomery RR, Retzinger GSAuthors
Robert R. Montgomery MD Emeritus Professor in the Pediatrics department at Medical College of WisconsinJohn Paul Scott MD Emeritus Professor in the Pediatrics department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
AfibrinogenemiaAmino Acid Sequence
Blood Platelets
Fibrinogen
Flocculation Tests
Formaldehyde
Humans
Kinetics
Molecular Sequence Data
Molecular Structure
Platelet Aggregation
Ristocetin
Surface Properties
von Willebrand Factor
