腺（嘌呤核）苷二磷酸：一种由腺嘌呤和核糖再加上两个磷酸组成的核苷酸。其中第二个磷酸以高能键与第一个磷酸结合。

• ADP (adensine diphosphate) A nucleotide consisting of adenine and ribose with two phosphate groups attached. The second phosphate is attached to the first by a high-energy bond.