3-Isopropylmalate dehydrogenase

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3-Isopropylmalate dehydrogenase
Identifiers
EC no. 1.1.1.85
CAS no. 9030-97-1
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MetaCyc metabolic pathway
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3-Isopropylmalate dehydrogenase (EC 1.1.1.85) is an enzyme that is a part of the isopropylmalate dehydrogenase family, which catalyzes the overall chemical reaction: [1] [2] [3] [4]

+ NAD+
 
 
 
H+
3-Isopropylmalate dehydrogenase
 
H+
 
+ CO2 + NADH
 

The first step is an oxidation reaction in which the cofactor, oxidised nicotinamide adenine dinucleotide (NAD+), converts the hydroxy group of the malic acid derivative into the corresponding keto group. This spontaneously decarboxylates to give the observed product. [5]

References

  1. Burns RO, Umbarger HE, Gross SR (1963). "The biosynthesis of leucine. III. The conversion of α-hydroxy-β-carboxyisocaproate to α-ketoisocaproate". Biochemistry. 2 (5): 1053–8. doi:10.1021/bi00905a024. PMID   14087358.
  2. Calvo JM, Stevens CM, Kalyanpur MG, Umbarger HE (December 1964). "The Absolute Configuration of α-carboxyisocaproic Acid (3-Isopropylmalic Acid), an Intermediate in Leucine Biosynthesis". Biochemistry. 3 (12): 2024–7. doi:10.1021/bi00900a043. PMID   14269331.
  3. Parsons SJ, Burns RO (February 1969). "Purification and Properties of β-Isopropylmalate Dehydrogenase". J. Biol. Chem. 244 (3): 996–1003. doi: 10.1016/S0021-9258(18)91884-3 . PMID   4889950.
  4. Németh A, Svingor A, Pócsik M, Dobó J, Magyar C, Szilágyi A, Gál P, Závodszky P (February 2000). "Mirror image mutations reveal the significance of an intersubunit ion cluster in the stability of 3-isopropylmalate dehydrogenase". FEBS Lett. 468 (1): 48–52. Bibcode:2000FEBSL.468...48N. doi:10.1016/S0014-5793(00)01190-X. PMID   10683439. S2CID   44544921.
  5. Enzyme 1.1.1.85 at KEGG Pathway Database.