Thus, as a general rule, cytoplasmic proteins contain free thiols, while proteins in other compartments such as the ER can possess disulfide bonds.

Which amino acids contain thiol?

Examples: The amino acid cysteine contains a thiol group.

Which enzymes contain thiol?

Thiol enzymes have single- or double-catalytic site cysteine residues and are redox active. Oxidoreductases and isomerases contain double-catalytic site cysteine residues, which are oxidized to a disulfide via a sulfenyl intermediate and reduced to a thiol or a thiolate.