Arginine residues as stabilizing elements in proteins

Arginine substitution for lysine in Actinoplanes D-xylose isomerase enhances protein heat stability in the presence of sugar substrates by affecting nonenzymatic glycation. Similar heat stability effects are noted with human copper, zinc superoxide dismutase and and D-glyceraldehyde phosphate dehydrogenase in Bacillus subtilis. Such selective amino acid substitution prevents interference in electrostatic interaction crucial for protein stability by preventing glycation. Thus, it has been shown that arginine confers stabilizing properties to proteins also shown by its increased concentration in thermophilic organisms.