amino acid side chain

例句：

1. 1.The protein is composed of amino acids.
   这个蛋白质由氨基酸组成。
2. 2. The structure of the protein is determined by the amino acid side chains.
   蛋白质的结构由氨基酸侧链决定。
3. 3.The amino acid side chains are responsible for the protein's function.
   氨基酸侧链负责蛋白质的功能。