The amino acids commonly found in proteins have the amino (-NH2) and carboxyl (-COO) H) groups attached to the same carbon atom; these are known as a-amino acids.

• 通常在蛋白质中的氨基酸其氨基(-NH2)和羧基(-cooH)基团连在同一个碳原子上;这些叫做a-氨基酸。