In enzymology, a dephospho-[reductase kinase] kinase ( EC 2.7.11.3) is an enzyme that catalyzes the chemical reaction

ATP + dephospho-{[hydroxymethylglutaryl-CoA reductase (NADPH)] kinase} ${\displaystyle \rightleftharpoons }$ ADP + {[hydroxymethylglutaryl-CoA reductase (NADPH)] kinase}

Thus, the two substrates of this enzyme are ATP and [[dephospho-{[hydroxymethylglutaryl-CoA reductase (NADPH)] kinase}]], whereas its two products are ADP and [[{[hydroxymethylglutaryl-CoA reductase (NADPH)] kinase}]].

This enzyme belongs to the family of transferases, specifically those transferring a phosphate group to the sidechain oxygen atom of serine or threonine residues in proteins ( protein-serine/threonine kinases). The systematic name of this enzyme class is ATP:dephospho-{[hydroxymethylglutaryl-CoA reductase (NADPH)] kinase} phosphotransferase. Other names in common use include AMP-activated kinase, AMP-activated protein kinase kinase, hydroxymethylglutaryl coenzyme A reductase kinase kinase, hydroxymethylglutaryl coenzyme A reductase kinase kinase, (phosphorylating), reductase kinase, reductase kinase kinase, and STK30.

References

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• Ingebritsen TS, Lee HS, Parker RA, Gibson DM (1978). "Reversible modulation of the activities of both liver microsomal hydroxymethylglutaryl coenzyme A reductase and its inactivating enzyme. Evidence for regulation by phosphorylation-dephosphorylation". Biochem. Biophys. Res. Commun. 81 (4): 1268–77. doi: 10.1016/0006-291X(78)91273-1. PMID  666819.
• Beg ZH, Stonik JA, Brewer HB Jr (1985). "Phosphorylation of hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase and modulation of its enzymic activity by calcium-activated and phospholipid-dependent protein kinase". J. Biol. Chem. 260 (3): 1682–7. doi: 10.1016/S0021-9258(18)89648-X. PMID  3155737.
• Clarke PR, Hardie DG (1990). "Regulation of HMG-CoA reductase: identification of the site phosphorylated by the AMP-activated protein kinase in vitro and in intact rat liver". EMBO J. 9 (8): 2439–46. doi: 10.1002/j.1460-2075.1990.tb07420.x. PMC  552270. PMID  2369897.
• Sato R, Goldstein JL, Brown MS (1993). "Replacement of serine-871 of hamster 3-hydroxy-3-methylglutaryl-CoA reductase prevents phosphorylation by AMP-activated kinase and blocks inhibition of sterol synthesis induced by ATP depletion". Proc. Natl. Acad. Sci. U.S.A. 90 (20): 9261–5. Bibcode: 1993PNAS...90.9261S. doi: 10.1073/pnas.90.20.9261. PMC  47547. PMID  8415689.