Transition-metal catalysts can be easier to handle than enzymes, but usually fail to distinguish between enantiomers.

过渡金属催化剂可能比酶更容易操作，无法区分对映体。

In other words, the two enantiomers are mirror images of each other.

也就是说，这两种对映体都是它们自己的镜像。

One of the most famous—or maybe infamous—examples of how two enantiomers affect the human body is methamphetamine.

关于两个对映体如何对人体产生影响，最著名——或许是最臭名昭著的例子之一就是甲基苯丙胺。

The S enantiomer is commonly sold over the counter as a vasodilator, and you can easily find it in vapor inhalers.

S对映体是作为血管舒张药在柜台销，你可以在蒸气吸入器中轻松找到它。

And that's because the different versions of chiral molecules—called enantiomers —are made up of all the same parts, but arranged differently.

这是因为手性分子的不同变体——即对映体——是由所有相同部分组成，是却以不同形式排列。

In the case of thalidomide, scientists discovered that the R enantiomer helped with morning sickness, but the S enantiomer caused those severe birth defects.

在萨力多胺中，科学家发现R对映体有助于缓解晨吐，是S对映体则会引发严重的先。

But if you position the " left-handed" , or S enantiomer, the same way, the hydrogen atom will be facing toward you.

是如果你找到的是“左撇子”或是S对映体，那么氢原子将面朝你。

But it turns out that thalidomide's R enantiomer can actually switch to the S version while inside the human body.

事实证明，萨力多胺中的R对映体在人体内还是可以转换成S变体。

These groups are kind of like your fingers: in each enantiomer, the groups are attached to the chiral center in the opposite order, so they're mirror images of each other.

在每个对映体中，这些组都逆序吸附在手性中心，因此它们变成了各自的镜像。

And because different receptors and enzymes inside your body react with molecules in very specific ways, the fact that enantiomers are mirror images means that they might react to things totally differently.

因为你体内不同的受体和酶会以非具体的方式和分子共同发生反应，事实上对映体是镜像意味着它们可能对事情的反应完全不同。

The result of these two pieces of work is a field called asymmetric organocatalysis (the asymmetric part of the name referring to its ability to generate pure enantiomers), that is now rippling through industrial chemistry.

这两项工作的结果是一个被称为不对称有机催化的领域（这个名称的不对称部分指的是它产生纯对映体的能力）现在正席卷工业化学界。

These are molecules that have two forms which are mirror images of each other. This is important in the drug industry, for the different versions, known as enantiomers, can have different effects in the body.

这些分子有两种形式且互为镜像。这在制药行业很重要，因为不同对映体，对人体会产生不同的作用。

Dr List and Dr MacMillan found a way to have the best of both worlds: small-molecule catalysts that have no metal atoms in them, can turn out pure enantiomers, and often simplify multi-step reactions. That has significant industrial implications.

不含金属原子的小分子催化剂，可以生成纯净的对映体，而且会简化多步反应。这具有重大的工业意义。

After researchers discovered that only the S version of thalidomide caused birth defects, they thought about isolating the R enantiomer so they could continue to use it to treat morning sickness.

当研究员门发现萨力多胺中仅有S变体会导致先后，他们考虑将R对映体隔离出来，这样他们就能够继续使用萨力多胺治疗晨吐。

If you position the version of the molecule that's considered " right-handed" , called the R enantiomer, so the closest oxygen atom to the chiral center is below it, the hydrogen atom attached to the center will be facing away from you.

如果你找到了认为是“右撇子”的分子变体，即R对映体，那么离手性中心最近的氧原子就在它的下方，附在中心的氢原子将背朝你。