BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Heavy metal salts, Ag+, Hg+ and Pb+ denature proteins by reacting with the sulfhydryl groups to form stable, metal-sulfur bonds. This prevents formation of needed disulfide bonds.

Detailed explanation-2: -A disulfide bond is a covalent bond between two sulfur atoms (–S–S–) formed by the coupling of two thiol (–SH) groups. Cysteine, one of 20 protein amino acids, has a –SH group in its side chain, and can easily be dimereized to cystine in aqueous solution by forming a disulfide bond.

Detailed explanation-3: -Disulfide bond formation generally occurs in the endoplasmic reticulum by oxidation. Therefore disulfide bonds are mostly found in extracellular, secreted and periplasmic proteins, although they can also be formed in cytoplasmic proteins under conditions of oxidative stress.

Detailed explanation-4: -Heavy metals and metalloids have been shown to inhibit refolding of chemically denatured proteins in vitro, to interfere with protein folding in vivo and to cause the aggregation of nascent proteins in living cells [7, 8, 9, 10].