Abnormalities in how indoleamine 2,3-dioxygenase enzyme activates as well as the metabolism of tryptophan-kynurenine may lead to excessive metabolism of tryptophan-kynurenine and lead to increased production of the neurotoxin quinolinic acid, contributing to major depression.

By making mice grow furrier coats, researchers have discovered that an enzyme known to serve as a last-ditch defense against cancer also activates adult stem cells, which the body uses to repair its tissues.

All these enzymes phosphorylate and thus activate MKK1 and/or MKK2 kinases, that are highly specific for ERK1 and ERK2.

All three enzymes activate a C-H bond adjacent to a carbonyl group.

Upon binding of the enzyme to the substrate:cofactor complex, the heavy:light chain interface is disrupted, and the enzyme activated by allostery.

But tamoxifen must be activated by a liver enzyme and, Dr. Flockhart of Indiana University and his colleagues found, not everyone's enzymes activate the drug.

Lipophilic second messenger molecules are derived from lipids residing in cellular membranes; enzymes stimulated by activated receptors activate the lipids by modifying them.

These enzymes activate and then deactivate various thyroid hormones and their metabolites.

A ubiquitin-activating enzyme or E1 first activates the ubiquitin by covalently attaching the molecule to its active site cysteine residue.

This enzyme activates ion Mg.