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

Structure and function of complement C5 convertase enzymes.

M K Pangburn1, N Rawal

  • 1Department of Biochemistry, University of Texas Health Science Center, Tyler 75708, USA. michael.pangbum@uthct.edu

Biochemical Society Transactions
|November 21, 2002
PubMed
Summary
This summary is machine-generated.

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

Search for Light Pseudoscalar Bosons, Pair-Produced in Higgs Boson Decays in the Four-Electron Final State in Proton-Proton Collisions at sqrt[s]=13  TeV.

Physical review letters·2026
Same author

First Evidence for Mixing-Induced CP Violation in B_{s}^{0}→J/ψϕ(1020) Decays in pp Collisions at sqrt[s]=13  TeV.

Physical review letters·2026
Same author

Observation of Suppressed Charged-Particle Production in Ultrarelativistic Oxygen-Oxygen Collisions.

Physical review letters·2026
Same author

Measurement of D^{0} Meson Photoproduction in Ultraperipheral Heavy Ion Collisions.

Physical review letters·2026
Same author

Observation of tWZ Production at the CMS Experiment.

Physical review letters·2026
Same author

First Exclusive Reconstruction of the B^{*+}, B^{*0}, and B_{s}^{*0} Mesons and Precise Measurement of Their Masses.

Physical review letters·2026
Same journal

TDP-43 proteinopathy as a biomarker and therapeutic target in amyotrophic lateral sclerosis.

Biochemical Society transactions·2026
Same journal

Advancing the monitoring of organelle contact sites in vitro and in vivo.

Biochemical Society transactions·2026
Same journal

Mechanisms influencing transient cytoplasmic protein targeting to intracellular lipid droplets.

Biochemical Society transactions·2026
Same journal

Replication associated nuclear DNA mismatch repair across kingdoms.

Biochemical Society transactions·2026
Same journal

Phosphatases of regenerating liver downregulate PTEN to promote tumorigenesis.

Biochemical Society transactions·2026
Same journal

Implications of Rho GTPase signaling in cancer immunotherapy.

Biochemical Society transactions·2026
See all related articles

Complement C5 convertases gain C5 specificity after cleaving C3. C3b deposition on these enzymes shifts their substrate preference from C3 to C5, initiating the membrane attack complex.

Area of Science:

  • Immunology
  • Biochemistry
  • Molecular Biology

Background:

  • The complement system is crucial for innate and adaptive immunity.
  • C5 convertases are key enzymes in the complement cascade, initiating the membrane attack complex.
  • These enzymes exhibit unique substrate specificity regulation.

Purpose of the Study:

  • To elucidate the mechanism by which C5 convertases acquire specificity for C5.
  • To investigate the role of C3 cleavage products in regulating C5 convertase activity.
  • To understand the switch in enzymatic activity from C3 to C5.

Main Methods:

  • Biochemical assays to measure enzyme kinetics (Km and Vmax).
  • Analysis of protein-protein interactions and complex formation.

Related Experiment Videos

  • Studies on the effect of C3b deposition on enzyme activity and specificity.

    • Main Results:

    • C5 convertases (classical/lectin: C4b2a; alternative: C3bBb) are intrinsically unstable.
    • Newly assembled enzymes preferentially cleave C3, with low affinity for C5.
    • Covalent deposition of C3b onto the enzyme significantly enhances C5 binding affinity (>1000-fold), switching specificity.

    Conclusions:

    • Enzymatic specificity for C5 is acquired post-cleavage of C3.
    • C3b deposition acts as a critical regulatory mechanism, tuning C5 convertase activity.
    • This substrate-induced specificity switch ensures efficient initiation of the membrane attack complex at microbial surfaces.