Related Experiment Video
Updated: Aug 14, 2026

Defining Substrate Specificities for Lipase and Phospholipase Candidates
Published on: November 23, 2016
[Comparative study of enzymatic activity of cholinesterases of different origin in thionaphthylacetate hydrolysis
Abstract:
A comparative determination of kinetic parameters V and Km in the reaction of hydrolysis thionaphthylacetate and well known substrate acetylthiocholine by choline esterases from different sources was conducted. It is shown that butyrylcholine esterases hydrolyze thionaphthylacetate with velocity comparable with that of hydrolysis of acetylthiocholine, while acetylcholine esterases and propionylcholine esterases hydrolyze this substrate several times slower than acetylthiocholine. The values of Km in the reactions of hydrolysis of thionaphthylacetate for all studied cholinesterases is an order higher than for acetylthiocholine except cholinesterase of blood serum of fish. This value for the latter enzyme is practically equal.
Related Concept Videos
Direct-Acting Cholinergic Agonists: Pharmacokinetics
Cholinesterases: Distribution and Function
Indirect-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
Reversible inhibitors display short to medium durations of action. Short-acting agents include simple alcohols with...
Indirect-Acting Cholinergic Agonists: Mechanism of Action
Reversible inhibitors like edrophonium bind to a specific part of the enzyme called the anionic catalytic site. They form noncovalent bonds, which means they are not strongly attached to the enzyme. This creates a temporary and less stable enzyme–inhibitor complex, leading to...
Indirect-Acting Cholinergic Agonists: Pharmacokinetics
Reversible agents containing quaternary amines, such as neostigmine and edrophonium, are not easily absorbed orally because they are...
Anticholinesterase Agents: Poisoning and Treatment
Irreversible agents form a strong bond with the cholinesterase enzyme, making it inactive. The breakdown of the phosphorylated enzyme is slower than the...

