5'-Nucleotidase, cytosolic IIIB (cN-IIIB)

5'-Nucleotidase, cytosolic IIIB (cN-IIIB; NT5C3B) is an intracellular enzyme catalyzing the hydrolytic dephosphorylation of nucleoside 5'-monophosphates, with a distinctive specificity for 7-methylguanosine monophosphate (m^7^GMP)[2][3]. This activity is thought to protect cells from inappropriate salvage and reincorporation of methylated nucleotides, thus maintaining nucleotide pool integrity[2]. Structurally, cN-IIIB belongs to the haloacid dehalogenase (HAD) superfamily, with a core Rossmannoid α/β domain and a smaller CAP domain that contributes to substrate specificity and active-site lid function[1][3]. While other 5'-nucleotidases (e.g., NT5C3A/cN-IIIA) have established clinical and disease relevance, no direct disease associations, drug inhibitors, or biomarker roles for NT5C3B are reported in the literature as of now[2][3]. The enzyme is predicted to localize in the cytosol and cytoplasm and plays a supporting role in nucleotide and RNA metabolism[2][3].

Other names

NT5C3Bcytosolic nucleotidase IIIB5NT3B