An asterisk before 'EC' indicates that this is an amendment to an existing enzyme rather than a new enzyme entry.
Recommended name: cytokinin dehydrogenase
Reaction: N6-dimethylallyladenine + electron acceptor = adenine + 3-methylbut-2-enal + reduced electron acceptor + H2O
Systematic name: N6-dimethylallyladenine:(acceptor) oxidoreductase
Comments: A flavoprotein(FAD). Converts zeatin and related cytokinins. Catalyses the oxidation of cytokinins, a family of N6-substituted adenine derivatives that are plant hormones, where the substituent is a dimethylallyl or other prenyl group. Although this activity was previously thought to be catalysed by a a hydrogen-peroxide-forming oxidase, this enzyme does not require oxygen for activity and does not form hydrogen peroxide. 2,6-Dichloroindophenol, methylene blue, nitroblue tetrazolium, phenazine methosulfate and Cu(II) in the presence of imidazole can act as acceptors.
References:
1. Galuszka, P., Frebort, I., Sebela, M., Jacobsen, S. and Pec, P. Cytokinin oxidase or dehydrogenase? Mechanism of cytokinin degradation in plants. Eur. J. Biochem. 268 (2001) 450-461. [Medline PMID: 11168382]
Recommended name: (S)-coclaurine-N-methyltransferase
Reaction: S-adenosyl-L-methionine + (S)-coclaurine = S-adenosyl-L-homocysteine + (S)-N-methylcoclaurine
For diagram click here.
Systematic name: S-adenosyl-L-methionine:(S)-coclaurine-N-methyltransferase
Comments: The enzyme is specific for the (S)-isomer of coclaurine. Norcoclaurine can also act as an acceptor.
References:
1. Loeffler, S., Deus-Neumann, B. and Zenk, M.H. S-Adenosyl-L-methionine: (S)-coclaurine-N-methyltransferase from Tinospora cordifolia. Phytochemistry 38 (1995) 1387-1395.
Recommended name: scyllo-inosamine-4-phosphate amidinotransferase
Reaction: L-arginine + 1-amino-1-deoxy-scyllo-inositol 4-phosphate = L-ornithine + 1-guanidino-1-deoxy-scyllo-inositol 4-phosphate
Other name(s): L-arginine:inosamine-P-amidinotransferase; inosamine-P amidinotransferase; L-arginine:inosamine phosphate amidinotransferase; inosamine-phosphate amidinotransferase
Systematic name: L-arginine:1-amino-1-deoxy-scyllo-inositol-4-phosphate amidinotransferase
Comments: 1D-1-Guanidino-3-amino-1,3-dideoxy-scyllo-inositol 6-phosphate, streptamine phosphate and 2-deoxystreptamine phosphate can also act as acceptors; canavanine can act as donor.
Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number: 52227-63-1
References:
1. Walker, M.S. and Walker, J.B. Enzymic studies on the biosynthesis of streptomycin, transamidation of inosamine and streptamine derivatives. J. Biol. Chem. 241 (1966) 1262-1269.
Recommended name: inositol 3-kinase
Reaction: ATP + myo-inositol = ADP + 1D-myo-inositol 3-phosphate
Other name(s): inositol-1-kinase (phosphorylating); myoinositol kinase; myo-inositol 1-kinase
Systematic name: ATP:myo-inositol 1-phosphotransferase
Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number: 37278-07-2
References:
1. English, P.D., Dietz, M. and Albersheim, P. Myoinositol kinase: partial purification and identification of product. Science 151 (1966) 198-199.
2. Molinari, E. and Hoffmann-Ostenhof, O. Studies on the biosynthesis of cyclitols. XXI. An enzyme system capable of phosphorylating myo-inositol to phytic acid. Hoppe-Seyler's Z. Physiol. Chem. 349 (1968) 1797-1799. [Medline UI: 69101297]
Recommended name: phospholipid-translocating ATPase
Reaction: ATP + H2O = ADP + phosphate
Other name(s): Mg2+-ATPase; flippase; aminophospholipid-transporting ATPase
Systematic name: ATP phosphohydrolase (phospholipid-flipping)
Comments: A P-type ATPase that undergoes covalent phosphorylation during the transport cycle. The enzyme apparently has several activities, one of them being the movement of phospholipids from one membrane face to the other ('flippase').
Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:
References:
1. Morris, M.B., Auland, M.E., Xu, Y.H. and Roufogalis, B.D. Characterization of the Mg2+-ATPase activity of the human erythrocyte membrane. Biochem. Mol. Biol. Int. 31 (1993) 823-832. [Medline UI: 94184211]
2. Vermeulen, W.P., Briede, J.J. and Rolofsen, B. Manipulation of the phosphatidylethanolamine pool in the human red cell membrane affects its Mg2+-ATPase activity. Mol. Membr. Biol. 13 (1996) 95-102. [Medline UI: 96436637]
3. Suzuki, H., Kamakura, M., Morii, M. and Takeguchi, N. The phospholipid flippase activity of gastric vesicles. J. Biol. Chem. 272 (1997) 10429-10434. [Medline UI: 97256755]
4. Auland ME, Roufogalis BD, Devaux PF, Zachowski A. Reconstitution of ATP-dependent aminophospholipid translocation in proteoliposomes. Proc Natl Acad Sci USA 91 (1994) 10938-10942. [Medline UI: 95062180]
Recommended name: Mg2+-importing ATPase
Reaction: ATP + H2O + Mg2+out = ADP + phosphate + Mg2+in
Systematic name: ATP phosphohydrolase (Mg2+-importing)
Comments: A P-type ATPase that undergoes covalent phosphorylation during the transport cycle. This enzyme occurs in both Gram-positive and Gram-negative bacteria, and three types are known, designated as CorA, MgtA and MgtB. The CorA itself is not an ATPase but an Mg2+ transporter.
Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:
References:
1. Tao, T., Snavely, M.D., Farr, S.G. and Maguire, M.E. Magnesium transport in Salmonella typhimurium: mtgA encodes a P-type ATPase and is regulated by Mg2+ in a manner similar to that of the mgtB P-type ATPase. J. Bacteriol. 177 (1995) 2654-2662. [Medline UI: 95270580]
2. Smith, R.L., Szegedy, M.A., Kucharski, L.M., Walker, C., Wiet, R.M., Redpath, A., Kaczmarek, M.T. and Maguire, M.E. The CorA Mg2+ transport protein of Salmonella typhimurium. Mutagenesis of conserved residues in the third membrane domain identifies a Mg2+ pore. J. Biol. Chem. 273 (1998) 28663-28669. [Medline UI: 99003207]
Recommended name: Zn2+-exporting ATPase
Reaction: ATP + H2O + Zn2+in = ADP + phosphate + Zn2+out
Other name(s): Zn(II)-translocating P-type ATPase
Systematic name: ATP phosphohydrolase (Zn2+-exporting)
Comments: A P-type ATPase that undergoes covalent phosphorylation during the transport cycle. This bacterial also exports Ni2+ and Co2+.
Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:
References:
1. Beard, S.J., Hashim, R., Membrillo-Hernandez, J., Hughes, M.N. and Poole, R.K. Zinc(II) tolerance in Escherichia coli K-12: evidence that the zntA gene (o732) encodes a cation transport ATPase. Mol. Micorbiol. 25 (1997) 883-891. [Medline UI: 98030196]
2. Rensing, C., Mitra, B. and Rosen, B.P. The zntA gene of Escherichia coli encodes a Zn(II)-translocating P-type ATPase. Proc. Natl. Acad. Sci. USA 94 (1997) 14326-14331. [Medline UI: 98070750]
3. Rensing, C., Sun, Y., Mitra, B. and Rosen, B.P. Pb(II)-translocating P-type ATPases. J. Biol. Chem. 273 (1998) 32614-32617. [Medline UI: 99047637]
Recommended name: Na+-exporting ATPase
Reaction: ATP + H2O + Na+in = ADP + phosphate + Na+out
Systematic name: ATP phosphohydrolase (Na+-exporting)
Comments: A P-type ATPase that undergoes covalent phosphorylation during the transport cycle. This enzyme from yeast is involved in the efflux of Na+, with one ion being exported per ATP hydrolysed.
Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:
References:
1. Wieland, J., Nitsche, A.M., Strayle, J., Steiner, H. and Rudolph, H.K. The PMR2 gene cluster encodes functionally distinct isoforms of a putative Na+ pump in the yeast plasma membrane. EMBO J. 14 (1995) 3870-3882. [Medline UI: 95393964]
2. Catty, P., de Kerchove d'Exaerde, A. and Goffeau, A. The complete inventory of the yeast Saccharomyces cerevisiae P-type transport ATPases. FEBS Lett. 409 (1997) 325-332. [Medline UI: 97367916]
3. Cheng, J., Guffanti, A.A. and Krulwich, T.A. A two-gene ABC-type transport system that extrudes Na+ in Bacillus subtilis is induced by ethanol or protonophore. Mol. Microbiol. 23 (1997) 1107-1120. [Medline UI: 97260108]
4. Saier, M.H., Jr. Molecular phylogeny as a basis for the classification of transport proteins from bacteria, archaea and eukarya. Adv. Microb. Physiol. 40 (1998) 81-136. [Medline UI: 99106651]
Recommended name: Ca2+-transporting ATPase
Reaction: ATP + H2O + Ca2+cis = ADP + phosphate + Ca2+trans
Other name(s): sarcoplasmic reticulum ATPase; sarco(endo)plasmic reticulum Ca2+-ATPase; calcium pump; Ca2+-pumping ATPase; plasma membrane Ca-ATPase
Systematic name: ATP phosphohydrolase (Ca2+-transporting)
Comments: A P-type ATPase that undergoes covalent phosphorylation during the transport cycle. This enzyme family comprises three types of Ca2+-transporting enzymes that are found in the plasma membrane, the sarcoplasmic reticulum and in yeast. The first and third transport one ion per ATP hydrolysed, whereas the second transports two ions.
Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:
References:
1. Schatzmann, H.J. and Vicenzi, F.F. Calcium movements across the membrane of human red cells. J. Physiol. 201 (1969) 369-395. [Medline UI: 69166882]
2. Inesi, G., Watanabe, T., Coan, C. and Murphy, A. The mechanism of sarcoplasmic reticulum ATPase. Ann. NY Acad. Sci. 402 (1982) 515-532. [Medline UI: 83176731]
3. Carafoli, E. The Ca2+ pump of the plasma membrane. J. Biol. Chem. 267 (1992) 2115-2118. [Medline UI: 92129274]
4. MacLennan, D.H., Rice, W.J. and Green, N.M. The mechanism of Ca2+ transport by sarco(endo)plasmic reticulum Ca2+-ATPases. J. Biol. Chem. 272 (1997) 28815-28818. [Medline UI: 98030547]
Recommended name: Na+/K+-exchanging ATPase
Reaction: ATP + H2O + Na+in + K+out = ADP + phosphate + Na+out + K+in
Systematic name: ATP phosphohydrolase (Na+/K+-exchanging)
Other name: sodium pump; Na+,K+ pump; Na,K-pump; (Na+ + K+)-activated ATPase; (Na+ + K+)-ATPase; Na+,K+-ATPase; Na,K-activated ATPase
Comments: A P-type ATPase that undergoes covalent phosphorylation during the transport cycle. This is a plasma membrane enzyme, ubiquitous in animal cells, that catalyses the efflux of three Na+ and influx of two K+ per ATP hydrolysed. It is involved in generating the plasma membrane electrical potential.
Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:
References:
1. Skou, J.C. The influence of some cations on an adenosinetriphosphatase from peripheral nerve. Biochim. Biophys. Acta 23 (1957) 394-401.
2. Post, R.L., Sen, A.K. and Rosenthal, A.S. A phosphorylated intermediate in adenosine triphosphate-dependent sodium and potassium transport across kidney membrane. J. Biol. Chem. 240 (1965) 1437-1445.
3. Skou, J.C. The energy-coupled exchange of Na+ for K+ across the cell membrane. The Na+,K+ pump. FEBS Lett. 268 (1990) 314-324. [Medline UI: 90346185]
[EC 3.6.3.13 Deleted entry: identical to EC 3.6.3.1 (EC 3.6.3.13 created 2000, deleted 2001)]
Recommended name: 6-pyruvoyltetrahydropterin synthase
Reaction: 6-[(1S,2R)-1,2-dihydroxy-3-triphosphooxypropyl]-7,8-dihydropterin = 6-pyruvoyl-5,6,7,8-tetrahydropterin + triphosphate
Systematic name: 2-amino-4-oxo-6-[(1S,2R)-1,2-dihydroxy-3-triphosphooxypropyl]-7,8-dihydroxypteridine triphosphate lyase
For diagram click here.
Comments: catalyses triphosphate elimination and an intramolecular redox reaction in the presence of Mg2+. It has been identified in human liver. The product is 6-pyruvoyltetrahydrobiopterin.
Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:
References:
1. Milstien, S., Kaufman, S. The biosynthesis of tetrahydrobiopterin in rat brain. Purification and characterization of 6-pyruvoyl-tetrahydrobiopterin(2'-oxo) reductase. J. Biol. Chem. 264 (1989) 8066-8073. [Medline UI: 89255238]
2. Thöny, B., Leimbacher, W., Bürgisser, D., Heinzmann, C.W. Human 6-pyruvoyl-tetrahydrobiopterin synthase: cDNA cloning and heterologous expression of the recombinant enzyme. Biochem. Biophys. Res. Commun. 189 (1992) 1437-1443. [Medline UI: 93129208]