Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

Allosteric modification of factor XIa functional activity upon binding to polyanions.

Dipali Sinha1, Karen O Badellino, Mariola Marcinkiewicz

  • 1The Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA. dipali@temple.edu

Biochemistry
|June 9, 2004
PubMed
Summary

Polyanions like dextran sulfate and heparin inhibit factor XIa activity and factor IX activation through an allosteric mechanism, not by blocking substrates. This binding alters enzyme conformation, reducing its function.

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

P1 and P2' site mutations convert protease nexin-2 from a factor XIa inhibitor to a plasmin inhibitor.

Journal of biochemistry·2012
Same author

The kunitz protease inhibitor domain of protease nexin-2 inhibits factor XIa and murine carotid artery and middle cerebral artery thrombosis.

Blood·2012
Same author

Productive recognition of factor IX by factor XIa exosites requires disulfide linkage between heavy and light chains of factor XIa.

The Journal of biological chemistry·2011
Same author

Mining the LIPG allelic spectrum reveals the contribution of rare and common regulatory variants to HDL cholesterol.

PLoS genetics·2011
Same author

The role of factor XIa (FXIa) catalytic domain exosite residues in substrate catalysis and inhibition by the Kunitz protease inhibitor domain of protease nexin 2.

The Journal of biological chemistry·2011
Same author

Determinants of affinity and proteolytic stability in interactions of Kunitz family protease inhibitors with mesotrypsin.

The Journal of biological chemistry·2010

Area of Science:

  • Biochemistry
  • Enzymology
  • Blood Coagulation

Background:

  • Factor XIa is a key enzyme in the intrinsic pathway of blood coagulation.
  • Understanding modulators of Factor XIa activity is crucial for hemostasis research.

Purpose of the Study:

  • To investigate the effects of polyanions, specifically dextran sulfate and heparin, on Factor XIa activity.
  • To elucidate the mechanism by which these polyanions inhibit Factor XIa and Factor IX activation.

Main Methods:

  • Enzyme kinetics assays using chromogenic substrate S-2366.
  • Measurement of Factor IX activation.
  • Fluorescence spectroscopy to study enzyme-polyanion interactions.

Main Results:

Related Experiment Videos

  • Dextran sulfate and heparin inhibited Factor XIa amidolytic activity and Factor IX activation in a dose-dependent manner.
  • Kinetic analysis indicated a decrease in Vmax without altering Km, suggesting non-competitive inhibition.
  • Fluorescence studies demonstrated an allosteric mechanism, with polyanions enhancing enzyme fluorescence and protecting a bound fluorophore.

    • Conclusions:

    • Polyanions, including dextran sulfate and heparin, inhibit Factor XIa through an allosteric mechanism.
    • This allosteric inhibition involves conformational changes in Factor XIa upon binding to polyanions.
    • The findings provide insights into the regulation of the intrinsic coagulation pathway.