uncompetitive inhibition

un·com·pet·i·tive in·hi·bi·tion

an inhibitory effect on a metabolic function, such as that of an enzyme, not based on competition for the binding site of the naturally occurring substrate but on a different effect on the molecule the function of which is being inhibited; an uncompetitive inhibition binds only to the enzyme-substrate complex.
References in periodicals archive ?
Although an alternative and simpler uncompetitive inhibition for GSSG also explains the atypical progress curves of enzyme activity of TGR, the noncompetitive inhibition pattern is more consistent with the existence of two sites.
Data represent mean [+ or -] standard deviation of the n replicates (in parenthesis); b: determined from the values of the theoretical rate constants and the definition of the corresponding kinetic parameter as derived from the mechanism-based model; c: an uncompetitive inhibition regarding GSSG; d: competitive inhibition regarding NADPH; nd not determined.
An explanation for this phenomenon is that fumarprotocetraric acid decreases Km (1.78 mM) and [V.sub.max] (64.5 [micro]M [min.sup.-1]) as its concentration is increased--a characteristic behavior of uncompetitive inhibition [52].
A typical characteristic of uncompetitive inhibition is that both [V.sub.max] and [K.sub.m] decrease in the presence of inhibitor.
Cornish-Bowden, "Why is uncompetitive inhibition so rare?
The models tested included pure and partial competitive inhibition, non-competitive inhibition, mixed-type inhibition, and uncompetitive inhibition [10,11].
SCH (Fong et al., 2007) and GOM (Wan et al., 2006) reverse Pgp-mediated MDR by uncompetitive inhibition of substrate-Pgp association and inducing Pgp conformational changes.
Our data did not allow a distinction between competitive, noncompetitive, or uncompetitive inhibition because of nonlinearity in the double reciprocal and Eadie-Hofstee plots.
The objective of the present study was the development of a quantitative liquid homogeneous immunoassay specific for theophylline based on the specific uncompetitive inhibition of inosine 5'-monophosphate dehydrogenase (IMPDH) by mycophenolic acid (MPA).
Uncompetitive inhibition occurs when MPA combines with the IMPDH-XMP complex at the active site of the enzyme to form IMPDH-XMP-MPA complex, which is unable to release XMP.
Likewise, there is no decrease in the inhibition degree at low substrate concentrations, which would be indicative of uncompetitive inhibition [21, 22].
Parallel slopes can be observed, indicating uncompetitive inhibition by engeletin in the manner similar to astilbin.