In contrast, when measured using peptide substrates, denaturants inhibit the enzyme.

However, mutagenesis studies have indicated that these residues are not individually essential for catalysis, as only mutations of two or more residues inhibit the enzyme.

Other cellular enzyme inhibitors are proteins that specifically bind to and inhibit an enzyme target.

Organophosphates inhibit an enzyme called acetylcholinesterase, causing a buildup of acetylcholine, excessive stimulation of all types of cholinergic neurons, and a wide range of symptoms.

These chemical compounds inhibit the enzyme acetylcholinesterase, preventing the normal breakdown of neurotransmitter acetylcholine.