Asparagine, abbreviated either as ASP or D, is one of the twenty common amino acids used by living organisms to build proteins. It is one of the neutral, polar amino acids. The side chain of asparagine is the amide group -CH2-C(O)-NH2. This side chain is capable of forming hydrogen bonds with other chemical entities that are electron donors. It is very similar to glutamine, which has one extra carbon on the side chain before the amide group, and aspartic acid, which has a hydroxyl group (OH) in place of the NH2 moiety on the side chain.