Sensitivity and robustness in covalent modification cycles with a bifunctional converter enzyme.

ABSTRACT: Regulation by covalent modification is a common mechanism to transmit signals in biological systems. The modifying reactions are catalyzed either by two distinct converter enzymes or by a single bifunctional enzyme (which may employ either one or two catalytic sites for its opposing activities). The reason for this diversification is unclear, but contemporary theoretical models predict that systems with distinct converter enzymes can exhibit enhanced sensitivity to input signals whereas bifunctional enzymes with two catalytic sites are believed to generate robustness against variations in system's components. However, experiments indicate that bifunctional enzymes can also exhibit enhanced sensitivity due to the zero-order effect, raising the question whether both phenomena could be unders

SUBMITTER: Straube R 

PROVIDER: S-EPMC3797581 | biostudies-literature | 2013 Oct

REPOSITORIES: biostudies-literature