Advanced

Differential changes in the association and dissociation rate constants for binding of cystatins to target proteinases occurring on N-terminal truncation of the inhibitors indicate that the interaction mechanism varies with different enzymes

Bjork, I; Pol, E; Raub-Segall, E; Abrahamson, Magnus LU ; Rowan, A D and Mort, J S (1994) In Biochemical Journal 299. p.219-225
Abstract
The importance of the N-terminal region of human cystatin C or chicken cystatin for the kinetics of interactions of the inhibitors with four cysteine proteinases was characterized. The association rate constants for the binding of recombinant human cystatin C to papain, ficin, actinidin and recombinant rat cathepsin B were 1.1 x 10(7), 7.0 x 10(6), 2.4 x 10(6) and 1.4 x 10(6) M-1.s-1, whereas the corresponding dissociation rate constants were 1.3 x 10(-7), 9.2 x 10(-6), 4.6 x 10(-2) and 3.5 x 10(-4) s-1. N-Terminal truncation of the first ten residues of the inhibitor negligibly affected the association rate constant with papain or ficin, but increased the dissociation rate constant approx. 3 x 10(4)- to 2 x 10(6)-fold. In contrast, such... (More)
The importance of the N-terminal region of human cystatin C or chicken cystatin for the kinetics of interactions of the inhibitors with four cysteine proteinases was characterized. The association rate constants for the binding of recombinant human cystatin C to papain, ficin, actinidin and recombinant rat cathepsin B were 1.1 x 10(7), 7.0 x 10(6), 2.4 x 10(6) and 1.4 x 10(6) M-1.s-1, whereas the corresponding dissociation rate constants were 1.3 x 10(-7), 9.2 x 10(-6), 4.6 x 10(-2) and 3.5 x 10(-4) s-1. N-Terminal truncation of the first ten residues of the inhibitor negligibly affected the association rate constant with papain or ficin, but increased the dissociation rate constant approx. 3 x 10(4)- to 2 x 10(6)-fold. In contrast, such truncation decreased the association rate constant with cathepsin B approx. 60-fold, while minimally affecting the dissociation rate constant. With actinidin, the truncated cystatin C had both an approx. 15-fold lower association rate constant and an approx. 15-fold higher dissociation rate constant than the intact inhibitor. Similar results were obtained for intact and N-terminally truncated chicken cystatin. The decreased affinity of human cystatin C or chicken cystatin for cysteine proteinases after removal of the N-terminal region is thus due to either a decreased association rate constant or an increased dissociation rate constant, or both, depending on the enzyme. This behaviour indicates that the contribution of the N-terminal segment of the two inhibitors to the interaction mechanism varies with the target proteinase as a result of structural differences in the active-site region of the enzyme. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biochemical Journal
volume
299
pages
219 - 225
publisher
Portland Press Limited
external identifiers
  • pmid:8166644
  • scopus:0028220189
ISSN
0264-6021
language
English
LU publication?
yes
id
8834d7d4-a64f-40a5-8527-74d1af0483a3 (old id 1107840)
alternative location
http://www.biochemj.org/bj/299/bj2990219.htm
date added to LUP
2008-07-22 16:07:36
date last changed
2017-07-30 04:30:39
@article{8834d7d4-a64f-40a5-8527-74d1af0483a3,
  abstract     = {The importance of the N-terminal region of human cystatin C or chicken cystatin for the kinetics of interactions of the inhibitors with four cysteine proteinases was characterized. The association rate constants for the binding of recombinant human cystatin C to papain, ficin, actinidin and recombinant rat cathepsin B were 1.1 x 10(7), 7.0 x 10(6), 2.4 x 10(6) and 1.4 x 10(6) M-1.s-1, whereas the corresponding dissociation rate constants were 1.3 x 10(-7), 9.2 x 10(-6), 4.6 x 10(-2) and 3.5 x 10(-4) s-1. N-Terminal truncation of the first ten residues of the inhibitor negligibly affected the association rate constant with papain or ficin, but increased the dissociation rate constant approx. 3 x 10(4)- to 2 x 10(6)-fold. In contrast, such truncation decreased the association rate constant with cathepsin B approx. 60-fold, while minimally affecting the dissociation rate constant. With actinidin, the truncated cystatin C had both an approx. 15-fold lower association rate constant and an approx. 15-fold higher dissociation rate constant than the intact inhibitor. Similar results were obtained for intact and N-terminally truncated chicken cystatin. The decreased affinity of human cystatin C or chicken cystatin for cysteine proteinases after removal of the N-terminal region is thus due to either a decreased association rate constant or an increased dissociation rate constant, or both, depending on the enzyme. This behaviour indicates that the contribution of the N-terminal segment of the two inhibitors to the interaction mechanism varies with the target proteinase as a result of structural differences in the active-site region of the enzyme.},
  author       = {Bjork, I and Pol, E and Raub-Segall, E and Abrahamson, Magnus and Rowan, A D and Mort, J S},
  issn         = {0264-6021},
  language     = {eng},
  pages        = {219--225},
  publisher    = {Portland Press Limited},
  series       = {Biochemical Journal},
  title        = {Differential changes in the association and dissociation rate constants for binding of cystatins to target proteinases occurring on N-terminal truncation of the inhibitors indicate that the interaction mechanism varies with different enzymes},
  volume       = {299},
  year         = {1994},
}