BIOMOLECULES AND ENZYMES

Detailed explanation-1: -The amino acid cysteine contains a sulfhydryl (-SH) group on its side chain. Sulfhydryls can be oxidized to form disulfide bonds in which two cysteine side chains, often from distant locations in the primary sequence, come together to form a sulfur-sulfur covalent bond (Figure 18).

Detailed explanation-2: -Sulfhydryls, also called thiols, exist in proteins in the side-chain of cysteine (Cys, C) amino acids.

Detailed explanation-3: -The cysteine amino acid group is the only amino acid capable of forming disulfide bonds, and thus can only do so with other cysteine groups.

Detailed explanation-4: -Methionine, cysteine, homocysteine, and taurine are the 4 common sulfur-containing amino acids, but only the first 2 are incorporated into proteins.