Tertiary and Quaternary Structure
Part I. D. Disulfide Bonds
D. Disulfide Bond - A weak covalent bond of tertiary structure.
The weak covalent bond is a disulfide between 2 Cys-SH:
Figure 7. Disulfide Bond Formation.
The most common disulfide bonds are intrachain and found most often in extracellular proteins, which face a tougher environment. Disulfide bonds usually formed during export of proteins. Formation of disulfides is enzyme catalyzed. Few -S--S- bonds are found in proteins in the cell because the environment is highly reducing.
©Wilbur H. Campbell, 1995; wcampbel@mtu.edu