简单的有机共价醯胺没有实际的天然来源,然而生命系统中的和蛋白质都是些带键的长链(聚合物),这些都是醯胺链接。

• "There are no practical natural sources of simple covalent amides, But the peptides and proteins in living systems are long chains (polymers) with peptide Bonds (see covalent Bond), which are amide linkages."