ABSTRACT
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
Parkin: “dk9272_c005” — 2007/7/19 — 22:30 — page 219 — #3
Proteins play a central role in biological systems. Although the information for evolution and biological organization of cells is contained in DNA, enzymes exclusively perform the chemical and biochemical processes that sustain the life of a cell/organism. Thousands of enzymes have been discovered. Each one of them catalyzes a highly specific biological reaction in cells. In addition to functioning as enzymes, proteins (such as collagen, keratin, elastin, etc.) also function as structural components of cells and complex organisms. The functional diversity of proteins essentially arises from their chemical make up.
