IUBMB Enzyme Nomenclature


Accepted name: nocturnin

Reaction: (1) NADPH + H2O = NADH + phosphate
(2) NADP+ + H2O = NAD+ + phosphate

Other name(s): NOCT (gene name); nocturnin (curled); MJ0109 (gene name); NADP phosphatase; NADPase

Systematic name: NADPH 2'-phosphohydrolase

Comments: The mammalian mitochondrial enzyme is a rhythmically expressed protein that regulates metabolism under the control of circadian clock. It has a slight preference for NADPH over NADP+. The archaeal enzyme, identified in Methanocaldococcus jannaschii, is bifunctional acting as NAD kinase (EC and NADP+ phosphatase with a slight preference for NADP+ over NADPH.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number:


1. Kawai, S. and Murata, K. Structure and function of NAD kinase and NADP phosphatase: key enzymes that regulate the intracellular balance of NAD(H) and NADP(H). Biosci. Biotechnol. Biochem. 72 (2008) 919-930. [PMID: 18391451]

2. Abshire, E.T., Chasseur, J., Bohn, J.A., Del Rizzo, P.A., Freddolino, P.L., Goldstrohm, A.C. and Trievel, R.C. The structure of human nocturnin reveals a conserved ribonuclease domain that represses target transcript translation and abundance in cells. Nucleic Acids Res. 46 (2018) 6257-6270. [PMID: 29860338]

3. Estrella, M.A., Du, J. and Korennykh, A. Crystal structure of human nocturnin catalytic domain. Sci. Rep. 8 (2018) 16294. [PMID: 30389976]

4. Estrella, M.A., Du, J., Chen, L., Rath, S., Prangley, E., Chitrakar, A., Aoki, T., Schedl, P., Rabinowitz, J. and Korennykh, A. The metabolites NADP+ and NADPH are the targets of the circadian protein nocturnin (curled). Nat. Commun. 10 (2019) 2367. [PMID: 31147539]

[EC created 2020]

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