limiting amino acid

例句：

1. 1.The protein is composed of a limited number of amino acids.
   这个蛋白质由有限的几种氨基酸组成。
2. 2. The body needs a certain amount of essential amino acids to function properly.
   身体需要一定量的必需氨基酸才能正常运作。
3. 3.The diet of the patient should be limited to those amino acids that are not easily obtained from food sources.
   患者的饮食应该仅限于那些不容易从食物来源中获得的氨基酸。