Substrates

Under construction!

AChE substrate

Solution of the three-dimensional (3D) structure of Torpedo californica acetylcholinesterase (TcAChE) in 1991 ^[1] opened up new horizons in research on an enzyme that had already been the subject of intensive investigation. The unanticipated structure of this extremely rapid enzyme, in which the active site was found to be buried at the bottom of a , lined by (colored dark magenta), led to a revision of the views then held concerning substrate traffic, recognition and hydrolysis ^[2]. This led to a series of theoretical and experimental studies, which took advantage of recent advances in theoretical techniques for treatment of proteins, such as

molecular dynamics and electrostatics and to site-directed mutagenesis, utilizing suitable expression systems. Acetylcholinesterase hydrolysizes the neurotransmitter acetylcholine , producing group. ACh directly binds (via its nucleophilic Oγ atom) within the (ACh/TcAChE structure 2ace). The residues are also important in the ligand recognition ^[3]. After this binding acetylcholinesterase ACh.

The Iron atom of CYP450 enzyme heme is a vital center for oxidation of substrates (drugs or other xenobiotics)

• Drug Metabolism by CYP450 Enzymes

Dihydrofolate reductase and its substrate dihydrofolate

• Malarial Dihydrofolate Reductase as Drug Target

In a substrate reduction therapy a small molecule inhibitor (Zavesca™) is used to inhibit the synthesis of the accumulated glucosylceramide.

NADH quinone oxidoreductase (NQO1) substrates

Quinones (including duroquinone (2,3,5,6-tetramethyl-p-benzoquinone) are substrates of NQO1 (it catalyzes two-electron reduction of them to hydroquinones). Duroquinone (yellow) binds to the by interactions involving the FAD and several hydrophobic and hydrophilic residues in the duroquinone-NQO1 complex (1dxo).