It interacts with a broad range of proteins by a redox mechanism based on reversible oxidation of 2 cysteine thiol groups to a disulfide, accompanied by the transfer of 2 electrons and 2 protons.
42.
Cysteine has traditionally been considered to be a hydrophilic amino acid, based largely on the chemical parallel between its thiol group and the hydroxyl groups in the side-chains of other polar amino acids.
43.
This acetate, bound to the active thiol group of coenzyme A, enters the " citric acid cycle " ( TCA cycle ) where it is fully cells to obtain energy from fat.
44.
The His343 residue at the active site of CRAT acts as a base that is able to deprotonate the CoA thiol group or the Carnitine 3-hydroxyl group depending on the direction of the reaction.
45.
Another suggestion is that methylation might be a detoxification if " As [ III ] intermediates are not permitted to accumulate " because the pentavalent organoarsenics have a lower affinity to thiol groups than inorganic pentavalent arsenics.
46.
Finally, a molecule of inorganic phosphate attacks the thioester and forms a tetrahedral intermediate, which then collapses to release 1, 3-bisphosphoglycerate, and the thiol group of the enzyme's cysteine residue.
47.
The thiol groups are also of great importance in substrate binding of enzymes, in metal-sulfur clusters in proteins ( e . g . ferredoxins ) and in regulatory proteins ( e . g . thioredoxins ).
48.
Here is the possible mechanism of action [ 2 ] : Firstly, the thiol group of FabF Cys163 is activated through the dipole moment of helix N-alpha-3 which lowers the pKa of this functional group.
49.
Since disulfide bond formation is an oxidative process, the major pathway of its catalysis has evolved to utilise oxidoreductases, which become reduced during the thiol-disulfide exchange reactions that oxidise the cysteine thiol groups of nascent polypeptides.
50.
"' 8-Mercaptoquinoline "'is the organosulfur compound with the formula C 9 H 7 NSH . It is a derivative of the heterocycle quinoline, substituted in the 8-position with a thiol group.
