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 2.7.1.23) and NADP+ phosphatase with a slight preference for NADP+ over NADPH.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number:
References:
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]