Evolution has provided a goodly range of these in the form of enzymes, which are large, complicated and sometimes temperamental protein molecules, but which have the advantage that they can create pure versions of what are known as optical isomers.

进化以酶的形式提供了大量的这类物质，这些酶是大型的、复杂的、有时还会变化无常的蛋白质分子，但它们的优点是可以产生被称为光学异构体的纯净版本。