Enzyme Structure and Kinetics

Imagine a living cell as a vast, densely packed metropolis where billions of precise chemical reactions must occur every second simply to keep the organism alive. If these reactions relied solely on the random, unassisted collisions of molecules at cellular temperatures, life would operate at a glacial pace, ultimately failing to sustain itself. This is the precise problem solved by enzymes, which are biological catalysts that speed up chemical reactions to the pace required for life. While the vast majority of biological enzymes are proteins, a vital evolutionary footnote exists in the form of ribozymes, which are RNA molecules capable of acting as biological catalysts. To understand how these molecular machines achieve their remarkable feats of acceleration, we must look beyond abstract chemical equations and examine the physical, three-dimensional geometry of the molecules themselves.

The three-dimensional architecture of a hammerhead ribozyme. While most biological catalysts are proteins, certain RNA molecules like this one can fold into highly specific shapes to catalyze chemical reactions.
The three-dimensional architecture of a hammerhead ribozyme. While most biological catalysts are proteins, certain RNA molecules like this one can fold into highly specific shapes to catalyze chemical reactions.