Open AccessShort-lived complexes between myelin basic protein peptides and IAk.
Author(s) -
Karen Mason,
Harden M. McConnell
Publication year - 1994
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.91.26.12463
Subject(s) - chemistry , peptide , myelin basic protein , reaction rate constant , dissociation constant , kinetics , dissociation (chemistry) , equilibrium constant , molecule , stereochemistry , myelin , biochemistry , organic chemistry , biology , receptor , physics , quantum mechanics , neuroscience , central nervous system
Kinetic rate constants and the equilibrium dissociation constant have been determined for the reaction between an affinity-purified class II major histocompatibility complex molecule IAk and a myelin basic protein analogue peptide, fluorescein-labeled Ac(1-14)A4C15. Under the experimental conditions used, the lifetime of the peptide-free IAk molecule with respect to inactivation is 3.1 hr. The equilibrium dissociation constant, 3.3 +/- 1.7 microM, is determined from measurements of the kinetics of peptide inhibition of IAk inactivation. The measured peptide dissociation halftime is relatively short, 30 min, and the deduced association rate is 100 M-1.s-1. The rate constants and the equilibrium constant are similar to those characteristic of kinetic intermediates in reactions of peptides and class II proteins that lead to long-lived terminal complexes.