5'-Nucleotide enzyme (5'-NT, EC 3.1.3.5), full name is 5'-ribonucleotide phosphohydrolase, is a special phosphohydrolase that specifically hydrolyzes 5'-phosphoric acid attached to pentose in 5'-nucleotide. This enzyme is widely distributed in the cell membrane of various tissues of human and animal. Only the 5'-NT released by the tissue cells of the hepatobiliary system may enter the blood. Therefore, the source of serum 5'-NT has certain specificity, and the determination of serum 5'-NT has important value for the diagnosis of hepatobiliary diseases.
