Abstract
This chapter looks at the fact that biochemists have investigated enzymes for more than 140 years, long before they had any realistic understanding of the physical basis of the living state. Using the technologies devised by biochemists, life scientists gradually determined the properties of biological systems. The chapter recounts how work on enzymes eventually demonstrated that almost every event in living organisms occurs because of enzyme-catalysed reactions. The chapter emphasizes how most of the thousands of biochemical reactions that sustain living processes occur at imperceptible rates without enzymes. Enzymes are, in fact, the means by which living organisms channel the flow of energy and matter.
