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Ultrasensitivity in biochemical systems controlled by covalent modification. Interplay between zero-order and multistep effects.

1984; Elsevier BV; Volume: 259; Issue: 23 Linguagem: Inglês

10.1016/s0021-9258(17)42619-6

1083-351X

Albert Goldbeter, Daniel E. Koshland,

Gene Regulatory Network Analysis

A previous analysis of covalent modification systems (Goldbeter, A., and Koshland, D. E., Jr. (1981) Proc. Natl. Acad. Sci. U. S. A. 78, 6840-6844) showed that steep transitions in the amount of modified protein can occur when the converter enzymes are saturated by their protein substrate. This ultrasensitivity can further be amplified when an effector acts at more than one step in a monocyclic or multicyclic cascade of covalent modification. We analyze the limitations of the latter multistep ultrasensitivity and show how it can combine with the zero-order effect to enhance the sensitivity of biochemical systems controlled by covalent modification.