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Your query returned 1 entry. 
Printable version
| EC | 2.3.1.328 | ||
| Accepted name: | branched-chain 2-oxoacid:malonyl-[acyl-carrier protein] acyltransferase | ||
| Reaction: | 4-methyl-2-oxopentanoate + malonyl-[acp] + a [lipoyl-carrier protein]-N6-[(R)-lipoyl]-L-lysine = 5-methyl-3-oxohexanoyl-[acp] + a [lipoyl-carrier protein]-N6-[(R)-dihydrolipoyl]-L-lysine + 2 CO2 (overall reaction) (1a) 4-methyl-2-oxopentanoate + a [lipoyl-carrier protein]-N6-[(R)-lipoyl]-L-lysine = a [lipoyl-carrier protein]-N6-[(3-methyl-2-oxobutanoyl)-(R)-lipoyl]-L-lysine + CO2 (1b) a [lipoyl-carrier protein]-N6-[(3-methyl-2-oxobutanoyl)-(R)-lipoyl]-L-lysine + malonyl-[acp] = 5-methyl-3-oxohexanoyl-[acp] + a [lipoyl-carrier protein]-N6-[(R)-dihydrolipoyl]-L-lysine + CO2 |
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| Glossary: | 4-methyl-2-oxopentanoate = 2-oxoisocaproate | ||
| Other name(s): | nasB (gene name) | ||
| Systematic name: | branched-chain 2-oxoacid:malonyl-[acyl-carrier protein] acyltransferase | ||
| Comments: | The enzyme, characterized from an environmental DNA sample and expressed in Paraburkholderia graminis, is a complex enzyme whose purpose is to divert branched-chain 2-oxo acids to production of branched-chain N-acyl amino acids by producing branched 3-oxoacyl-[acp] molecules. NasB accepts branched-chain 2-oxoacids such as 4-methyl-2-oxopentanoate, and catalyses a decarboxylative transfer to a thiamine diphosphate cofactor, followed by a transfer to a lipoyl cofactor, and finally a second decarboxylative transfer to the malonyl-[acp] acceptor. The products, such as 5-methyl-3-oxohexanoyl-[acp], can be extended by the fatty acid synthase system to form branched long-chain fatty-acyl-[acp] molecules, which serve as substrates for EC 2.3.1.327, long-chain acyl-[acp]:L-phenylalanine N-acyltransferase (NasA). During the reaction the lipoyl cofactor is reduced to dihydrolipoyl, which must be oxidized back to lipoyl by an unknown enzyme. | ||
| Links to other databases: | BRENDA, EXPASY, KEGG, MetaCyc | ||
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