Chapter 24, Problem 24.40SP

Lipoic acid is often found near the active sites of enzymes, usually bound to the peptide by a long flexible amide linkage with a lysine residue.

1. a. Is lipoic acid a mild oxidizing agent or a mild reducing agent? Draw it in both its oxidized and reduced forms.
2. b. Show how lipoic acid might react with two Cys residues to form a disulfide bridge.
3. c. Give a balanced equation for the hypothetical oxidation or reduction, as you predicted in part (a), of an aldehyde by lipoic acid.