What is an Enzyme and What do Enzymes do?

Enzymes have been misunderstood almost as much as instruction manuals for VCRs. Everyone know that enzymes play essential roles in all living things, but what exactly are they?

Are they alive, like bacteria? No. They’re chemicals, almost all of them proteins, that accelerate the complex chemical reactions essential to living things, both plant and animal. In other words, they are catalysts, substances that help chemical reactions go faster but are not used up in the process. Without enzymes, the chemistry of life would be impossibly slow, if it proceeded at all.

An enzyme molecule does its catalyzing job when a specific part of it, called its active site, reacts with a specific chemical, called its substrate, enabling that substrate to take part in vital chemical processes thousands or millions of times faster than it ordinarily would. The molecules of each type of enzyme have a unique shape that can react with only one specific substrate, thereby catalyzing only one specific chemical reaction. There is a unique enzyme for each of the hundreds of chemical reactions essential to the lives of all plants and animals.

For example, the dissolving of waste carbon dioxide from our bodily tissues into our bloodstreams and the “undissolving” of it back to gas for exhalation from our lungs are absolutely essential life processes. But if it weren’t for the enzyme carbonic anhydrase, these processes would take place so slowly that we couldn’t survive. Carbonic anhydrase makes the processes happen ten million times faster. Each carbonic anhydrase molecule can perform its speed-up act on a million carbon dioxide molecules per second.

An enzyme is named by tacking the suffix -ase onto a brief description of what it does. The tea enzyme is named polyphenol oxidase because it oxidizes polyphenols. If there were such a thing as an enzyme that speeds up the glazing of pottery, it might be called a vase glazease.