The Enzyme Database

Your query returned 5 entries.    printer_iconPrintable version



EC 1.1.1.87     
Accepted name: homoisocitrate dehydrogenase
Reaction: (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate + NAD+ = 2-oxoadipate + CO2 + NADH + H+
For diagram of l-lysine synthesis, click here
Glossary: homoisocitrate = (-)-threo-homoisocitrate = (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate
Other name(s): 2-hydroxy-3-carboxyadipate dehydrogenase; 3-carboxy-2-hydroxyadipate dehydrogenase; homoisocitric dehydrogenase; (-)-1-hydroxy-1,2,4-butanetricarboxylate:NAD+ oxidoreductase (decarboxylating); 3-carboxy-2-hydroxyadipate:NAD+ oxidoreductase (decarboxylating); HICDH
Systematic name: (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate:NAD+ oxidoreductase (decarboxylating)
Comments: Forms part of the lysine biosynthesis pathway in fungi [3].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 9067-90-7
References:
1.  Strassman, M. and Ceci, L.N. Enzymatic formation of α-ketoadipic acid from homoisocitric acid. J. Biol. Chem. 240 (1965) 4357–4361. [PMID: 4284830]
2.  Rowley, B. and Tucci, A.F. Homoisocitric dehydrogenase from yeast. Arch. Biochem. Biophys. 141 (1970) 499–510. [DOI] [PMID: 4395693]
3.  Zabriskie, T.M. and Jackson, M.D. Lysine biosynthesis and metabolism in fungi. Nat. Prod. Rep. 17 (2000) 85–97. [PMID: 10714900]
[EC 1.1.1.87 created 1972 (EC 1.1.1.155 created 1976, incorporated 2004)]
 
 
EC 1.1.1.155      
Deleted entry: homoisocitrate dehydrogenase. The enzyme is identical to EC 1.1.1.87, homoisocitrate dehydrogenase
[EC 1.1.1.155 created 1976, deleted 2004]
 
 
EC 1.1.1.286     
Accepted name: isocitrate—homoisocitrate dehydrogenase
Reaction: (1) isocitrate + NAD+ = 2-oxoglutarate + CO2 + NADH
(2) (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate + NAD+ = 2-oxoadipate + CO2 + NADH + H+
Glossary: isocitrate = (1R,2S)-1-hydroxypropane-1,2,3-tricarboxylate (previously known as threo-Ds-isocitrate)
homoisocitrate = (-)-threo-homoisocitrate = (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate
Other name(s): homoisocitrate—isocitrate dehydrogenase; PH1722
Systematic name: isocitrate(homoisocitrate):NAD+ oxidoreductase (decarboxylating)
Comments: Requires Mn2+ and K+ or NH4+ for activity. Unlike EC 1.1.1.41, isocitrate dehydrogenase (NAD+) and EC 1.1.1.87, homoisocitrate dehydrogenase, this enzyme, from Pyrococcus horikoshii, can use both isocitrate and homoisocitrate as substrates. The enzyme may play a role in both the lysine and glutamate biosynthesis pathways.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Miyazaki, K. Bifunctional isocitrate-homoisocitrate dehydrogenase: a missing link in the evolution of β-decarboxylating dehydrogenase. Biochem. Biophys. Res. Commun. 331 (2005) 341–346. [DOI] [PMID: 15845397]
[EC 1.1.1.286 created 2005]
 
 
EC 4.2.1.36     
Accepted name: homoaconitate hydratase
Reaction: (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate = (Z)-but-1-ene-1,2,4-tricarboxylate + H2O
For diagram of l-lysine synthesis, click here
Glossary: cis-homoaconitate = (Z)-but-1-ene-1,2,4-tricarboxylate
(R)-homocitrate = (2R)-2-hydroxybutane-1,2,4-tricarboxylate
homoisocitrate = (-)-threo-homoisocitrate = (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate
Other name(s): homoaconitase; cis-homoaconitase; HACN; Lys4; LysF; 2-hydroxybutane-1,2,4-tricarboxylate hydro-lyase (incorrect)
Systematic name: (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate hydro-lyase [(Z)-but-1-ene-1,2,4-tricarboxylate-forming]
Comments: Requires a [4Fe-4S] cluster for activity. The enzyme from the hyperthermophilic eubacterium Thermus thermophilus can catalyse the reaction shown above but cannot catalyse the previously described reaction, i.e. formation of (R)-homocitrate by hydration of cis-homoaconitate. The enzyme responsible for the conversion of cis-homoaconitate into (R)-homocitrate in T. thermophilus is unknown at present but the reaction can be catalysed in vitro using aconitate hydratase from pig (EC 4.2.1.3) [2].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 9030-68-6
References:
1.  Strassman, M. and Ceci, L.N. Enzymatic formation of cis-homoaconitic acid, an intermediate in lysine biosynthesis in yeast. J. Biol. Chem. 241 (1966) 5401–5407. [PMID: 5954805]
2.  Jia, Y., Tomita, T., Yamauchi, K., Nishiyama, M. and Palmer, D.R. Kinetics and product analysis of the reaction catalysed by recombinant homoaconitase from Thermus thermophilus. Biochem. J. 396 (2006) 479–485. [DOI] [PMID: 16524361]
3.  Zabriskie, T.M. and Jackson, M.D. Lysine biosynthesis and metabolism in fungi. Nat. Prod. Rep. 17 (2000) 85–97. [PMID: 10714900]
[EC 4.2.1.36 created 1972, modified 2007]
 
 
EC 4.2.1.114     
Accepted name: methanogen homoaconitase
Reaction: (R)-2-hydroxybutane-1,2,4-tricarboxylate = (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate (overall reaction)
(1a) (R)-2-hydroxybutane-1,2,4-tricarboxylate = (Z)-but-1-ene-1,2,4-tricarboxylate + H2O
(1b) (Z)-but-1-ene-1,2,4-tricarboxylate + H2O = (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate
For diagram of the 2-aminoadipate pathway of L-lysine synthesis, click here
Glossary: cis-homoaconitate = (Z)-but-1-ene-1,2,4-tricarboxylate
(R)-homocitrate = (R)-2-hydroxybutane-1,2,4-tricarboxylate
homoisocitrate = (–)-threo-homoisocitrate = (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate
Other name(s): methanogen HACN
Systematic name: (R)-2-hydroxybutane-1,2,4-tricarboxylate hydro-lyase [(1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate-forming]
Comments: This enzyme catalyses several reactions in the pathway of coenzyme-B biosynthesis in methanogenic archaea. Requires a [4Fe-4S] cluster for activity. In contrast to EC 4.2.1.36, homoaconitate hydratase, this enzyme can catalyse both the dehydration of (R)-homocitrate to form cis-homoaconitate and the subsequent hydration reaction that forms homoisocitrate. In addition to cis-homoaconitate, the enzyme can also catalyse the hydration of the physiological substrates dihomoaconitate and trihomoaconitate as well as the non-physiological substrate tetrahomoaconitate. cis-Aconitate and threo-DL-isocitrate cannot act as substrates, and (S)-homocitrate and trans-homoaconitate act as inhibitors of the enzyme.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB
References:
1.  Drevland, R.M., Jia, Y., Palmer, D.R. and Graham, D.E. Methanogen homoaconitase catalyzes both hydrolyase reactions in coenzyme B biosynthesis. J. Biol. Chem. 283 (2008) 28888–28896. [DOI] [PMID: 18765671]
[EC 4.2.1.114 created 2009]
 
 


Data © 2001–2021 IUBMB
Web site © 2005–2021 Andrew McDonald