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MetaCyc Reaction: 1.8.1.4

Superclasses: Reactions Classified By Conversion TypeSimple ReactionsChemical ReactionsProtein-Modification Reactions
Reactions Classified By SubstrateMacromolecule ReactionsProtein-ReactionsProtein-Modification Reactions

EC Number: 1.8.1.4

Enzymes and Genes:

Advenella mimigardefordensis DPN7: dehydrolipoamide dehydrogenase: lpdA
Ascaris suum: dihydrolipoyl dehydrogenase: DLD
Bacillus subtilis: dihydrolipoyl dehydrogenase componentInferred from experiment: pdhD
Escherichia coli K-12 substr. MG1655: lipoamide dehydrogenaseInferred from experiment: lpd
Homo sapiens: dihydrolipoyl dehydrogenaseInferred from experiment: DLD
Synechococcus elongatus PCC 7942: pyruvate dehydrogenase complex E3 component: pdhD
dihydrolipoamide dehydrogenase: Synpcc7942_1198

Sub-reaction of:
2-oxoglutarate + coenzyme A + NAD+ → succinyl-CoA + CO2 + NADH

In Pathway: 2-oxoglutarate decarboxylation to succinyl-CoA

Supersedes EC number: 1.6.4.3

Note that this reaction equation differs from the official Enzyme Commission reaction equation for this EC number, which can be found here .

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the Enzyme Commission system.

Most BioCyc compounds have been protonated to a reference pH value of 7.3. Please see the PGDB Concepts Guide for more information.

Mass balance status: Balanced.

Direct generic reaction:
a [lipoyl-carrier protein] N6-dihydrolipoyl-L-lysine + NAD+ → a [lipoyl-carrier protein]-N6-lipoyl-L-lysine + NADH + H+ (1.8.1.4)

Enzyme Commission Primary Name: dihydrolipoyl dehydrogenase

Enzyme Commission Synonyms: LDP-Glc, LDP-Val, dehydrolipoate dehydrogenase, diaphorase, dihydrolipoamide dehydrogenase, dihydrolipoamide:NAD+ oxidoreductase, dihydrolipoic dehydrogenase, dihydrothioctic dehydrogenase, lipoamide dehydrogenase (NADH), lipoamide oxidoreductase (NADH), lipoamide reductase, lipoamide reductase (NADH), lipoate dehydrogenase, lipoic acid dehydrogenase, lipoyl dehydrogenase, protein-6-N-(dihydrolipoyl)lysine:NAD+ oxidoreductase

Standard Gibbs Free Energy (ΔrG in kcal/mol): 19.404053Inferred by computational analysis [Latendresse13]

Summary:
A flavoprotein (FAD). A component of the multienzyme 2-oxo-acid dehydrogenase complexes. In the pyruvate dehydrogenase complex, it binds to the core of EC 2.3.1.12, dihydrolipoyllysine-residue acetyltransferase, and catalyses oxidation of its dihydrolipoyl groups. It plays a similar role in the oxoglutarate and 3-methyl-2-oxobutanoate dehydrogenase complexes. Another substrate is the dihydrolipoyl group in the H-protein of the glycine-cleavage system (click here for diagram), in which it acts, together with EC 1.4.4.2, glycine dehydrogenase (decarboxylating), and EC 2.1.2.10, aminomethyltransferase, to break down glycine. It can also use free dihydrolipoate, dihydrolipoamide or dihydrolipoyllysine as substrate. This enzyme was first shown to catalyse the oxidation of NADH by methylene blue; this activity was called diaphorase. The glycine cleavage system is composed of four components that only loosely associate: the P protein ( EC 1.4.4.2), the T protein ( EC 2.1.2.10), the L protein ( EC 1.8.1.4) and the lipoyl-bearing H protein [Nesbitt05].

Enzyme Commission Summary:
A flavoprotein (FAD). A component of the multienzyme 2-oxo-acid dehydrogenase complexes. In the pyruvate dehydrogenase complex, it binds to the core of EC 2.3.1.12, dihydrolipoyllysine-residue acetyltransferase, and catalyses oxidation of its dihydrolipoyl groups. It plays a similar role in the oxoglutarate and 3-methyl-2-oxobutanoate dehydrogenase complexes. Another substrate is the dihydrolipoyl group in the H-protein of the glycine-cleavage system (click here for diagram), in which it acts, together with EC 1.4.4.2, glycine dehydrogenase (decarboxylating), and EC 2.1.2.10, aminomethyltransferase, to break down glycine. It can also use free dihydrolipoate, dihydrolipoamide or dihydrolipoyllysine as substrate. This enzyme was first shown to catalyse the oxidation of NADH by methylene blue; this activity was called diaphorase. The glycine cleavage system is composed of four components that only loosely associate: the P protein ( EC 1.4.4.2), the T protein ( EC 2.1.2.10), the L protein ( EC 1.8.1.4) and the lipoyl-bearing H protein [Nesbitt05].

Citations: [Massey60, Savage57, Straub39, Perham00]

Gene-Reaction Schematic

Gene-Reaction Schematic

Instance reactions of [a [lipoyl-carrier protein] N6-dihydrolipoyl-L-lysine + NAD+ → a [lipoyl-carrier protein]-N6-lipoyl-L-lysine + NADH + H+] (1.8.1.4):
i1: an [apo BCAA dehydrogenase E2 protein] N6-dihydrolipoyl-L-lysine + NAD+ ↔ an [apo BCAA dehydrogenase E2 protein] N6-lipoyl-L-lysine + NADH + H+ (1.8.1.4)

i2: a [glycine-cleavage complex H protein] N6-dihydrolipoyl-L-lysine + NAD+ ↔ a [glycine-cleavage complex H protein] N6-lipoyl-L-lysine + NADH + H+ (1.8.1.4)

i3: a [2-oxoglutarate dehydrogenase E2 protein] N6-dihydrolipoyl-L-lysine + NAD+ ↔ a [2-oxoglutarate dehydrogenase E2 protein] N6-lipoyl-L-lysine + NADH + H+ (1.8.1.4)
i4: a [pyruvate dehydrogenase E2 protein] N6-dihydrolipoyl-L-lysine + NAD+ ↔ a [pyruvate dehydrogenase E2 protein] N6-lipoyl-L-lysine + NADH + H+ (1.8.1.4)

Relationship Links: BRENDA:EC:1.8.1.4, ENZYME:EC:1.8.1.4, IUBMB-ExplorEnz:EC:1.8.1.4

Credits:
Revised 18-Sep-2012 by Caspi R, SRI International


References

Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

Massey60: Massey V, Gibson QH, Veeger C (1960). "Intermediates in the catalytic action of lipoyl dehydrogenase (diaphorase)." Biochem J 77;341-51. PMID: 13767908

Nesbitt05: Nesbitt NM, Baleanu-Gogonea C, Cicchillo RM, Goodson K, Iwig DF, Broadwater JA, Haas JA, Fox BG, Booker SJ (2005). "Expression, purification, and physical characterization of Escherichia coli lipoyl(octanoyl)transferase." Protein Expr Purif 39(2);269-82. PMID: 15642479

Perham00: Perham RN (2000). "Swinging arms and swinging domains in multifunctional enzymes: catalytic machines for multistep reactions." Annu Rev Biochem 69;961-1004. PMID: 10966480

Savage57: Savage N (1957). "Preparation and properties of highly purified diaphorase." Biochem J 67(1);146-55. PMID: 13471525

Straub39: Straub FB (1939). "Isolation and properties of a flavoprotein from heart muscle tissue." Biochem J 33(5);787-92. PMID: 16746974


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by Pathway Tools version 19.5 (software by SRI International) on Wed Feb 10, 2016, biocyc13.