There are 20 common amino acids, and we typically designate them with single-letter abbreviations, so it's really an alphabet of amino acids.

一共有 20 种常见的氨基酸，我们通常用单个字母的缩写来给他们命名，就像是氨基酸的字母表。

The building blocks for these polymers go well beyond the 20 common amino acids used to make proteins.

这些聚合物的组成部分远远超出了用于制造蛋白质的 20 种常见氨基酸。

Sodium, which is well-established as an essential part of our diet, and glutamate, a very common amino acid found in numerous plant and animal proteins.

一种是纳，它被公认为我们饮食中不可或缺的一部分，另一种则是谷氨酸，一种非常常见的氨基酸存在于多种动植物蛋白质中。

People with PKU are unable to properly metabolize or digest phenylalanine, which is one of the 20 common amino acids that we've been talking about.

患有 PKU 的人无法正确代谢或消化苯丙氨酸，苯丙氨酸是我们一直在谈论的 20 种常见氨基酸之一。

The translational machinery of natural cells -- including ribosomes, aminoacyl-tRNA synthetase enzymes and tRNAs -- is a unique and special system for making proteins in which the 20 common amino acids are strung together in a chain.

天然细胞的翻译机制——包括核糖体、氨酰-tRNA 合成酶和 tRNA——是一种独特而特殊的系统，用于制造蛋白质，其中 20 种常见氨基酸串成一条链。