Mechanisms of signaling and related enzymes

TLDR: From kinetic studies of mutant and metal ion substituted enzymes, the catalytic powers of cell signaling and related enzymes can be rationalized quantitatively by factors contributed by metal ion catalysis (≥105), general acid catalysis, general baseCatalysis, and transition‐state stabilization by cationic and hydrogen bond donating residues (≈103±1).

Abstract: Most enzymes involved in cell signaling, such as protein kinases, protein phosphatases, GTPases, and nucleotide cyclases catalyze nucleophilic substitutions at phosphorus When possible, the mechanisms of such enzymes are most clearly described quantitatively in terms of how associative or dissociative they are The mechanisms of cell signaling enzymes range from or = 10(5), general acid catalysis (approximately 10(3 +/- 1)), general base catalysis (approximately 10(3 +/- 1)), and transition-state stabilization by cationic and hydrogen bond donating residues (approximately 10(3 +/- 1))