Reaction: an octanoyl-[acyl-carrier protein] + a protein = a protein N6-(octanoyl)lysine + an [acyl-carrier protein]
Glossary: lipoyl group
Other name(s): LipB; lipoyl (octanoyl)-[acyl-carrier-protein]-protein N-lipoyltransferase; lipoyl (octanoyl)-acyl carrier protein:protein transferase; lipoate/octanoate transferase; lipoyltransferase; octanoyl-[acyl carrier protein]-protein N-octanoyltransferase; lipoyl(octanoyl)transferase; octanoyl-[acyl-carrier-protein]:protein N-octanoyltransferase
Systematic name: octanoyl-[acyl-carrier protein]:protein N-octanoyltransferase
Comments: This is the first committed step in the biosynthesis of lipoyl cofactor. Lipoylation is essential for the function of several key enzymes involved in oxidative metabolism, as it converts apoprotein into the biologically active holoprotein. Examples of such lipoylated proteins include pyruvate dehydrogenase (E2 domain), 2-oxoglutarate dehydrogenase (E2 domain), the branched-chain 2-oxoacid dehydrogenases and the glycine cleavage system (H protein) [2,3]. Lipoyl-ACP can also act as a substrate [4] although octanoyl-ACP is likely to be the true substrate [6] . The other enzyme involved in the biosynthesis of lipoyl cofactor is EC 2.8.1.8, lipoyl synthase. An alternative lipoylation pathway involves EC 6.3.1.20, lipoate—protein ligase, which can lipoylate apoproteins using exogenous lipoic acid (or its analogues).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 392687-64-8
References:
1. Nesbitt, N.M., Baleanu-Gogonea, C., Cicchillo, R.M., Goodson, K., Iwig, D.F., Broadwater, J.A., Haas, J.A., Fox, B.G. and Booker, S.J. Expression, purification, and physical characterization of Escherichia coli lipoyl(octanoyl)transferase. Protein Expr. Purif. 39 (2005) 269-282. [PMID: 15642479]
2. Vanden Boom, T.J., Reed, K.E. and Cronan, J.E., Jr. Lipoic acid metabolism in Escherichia coli: isolation of null mutants defective in lipoic acid biosynthesis, molecular cloning and characterization of the E. coli lip locus, and identification of the lipoylated protein of the glycine cleavage system. J. Bacteriol. 173 (1991) 6411-6420. [PMID: 1655709]
3. Jordan, S.W. and Cronan, J.E., Jr. A new metabolic link. The acyl carrier protein of lipid synthesis donates lipoic acid to the pyruvate dehydrogenase complex in Escherichia coli and mitochondria. J. Biol. Chem. 272 (1997) 17903-17906. [PMID: 9218413]
4. Zhao, X., Miller, J.R., Jiang, Y., Marletta, M.A. and Cronan, J.E. Assembly of the covalent linkage between lipoic acid and its cognate enzymes. Chem. Biol. 10 (2003) 1293-1302. [PMID: 14700636]
5. Wada, M., Yasuno, R., Jordan, S.W., Cronan, J.E., Jr. and Wada, H. Lipoic acid metabolism in Arabidopsis thaliana: cloning and characterization of a cDNA encoding lipoyltransferase. Plant Cell Physiol. 42 (2001) 650-656. [PMID: 11427685]
6. Perham, R.N. Swinging arms and swinging domains in multifunctional enzymes: catalytic machines for multistep reactions. Annu. Rev. Biochem. 69 (2000) 961-1004. [PMID: 10966480]