Loading Pathway...
Error: Pathway image not found.
Hide
Pathway Description
Leucine Biosynthesis
Escherichia coli
Metabolic Pathway
Leucine biosynthesis involves a five-step conversion process starting with the valine precursor 2-keto-isovalerate interacting with acetyl-CoA and water through a 2-isopropylmalate synthase resulting in Coenzyme A, hydrogen Ion and 2-isopropylmalic acid. The latter compound reacts with isopropylmalate isomerase which dehydrates the compound resulting in a Isopropylmaleate. This compound reacts with water through a isopropylmalate isomerase resulting in 3-isopropylmalate. This compound interacts with a NAD-driven D-malate / 3-isopropylmalate dehydrogenase results in 2-isopropyl-3-oxosuccinate. This compound interacts spontaneously with hydrogen resulting in the release of carbon dioxide and ketoleucine. Ketoleucine interacts in a reversible reaction with L-glutamic acid through a branched-chain amino-acid aminotransferase resulting in Oxoglutaric acid and L-leucine. L-leucine can then be exported outside the cytoplasm through a transporter: L-amino acid efflux transporter. In the final step, ketoleucine can be catalyzed to form L-leucine by branched-chain amino-acid aminotransferase (IlvE) and tyrosine aminotransferase (TryB). L-Glutamic acid can also be transformed into oxoglutaric acid by these two enzymes. Tyrosine aminotransferase can be suppressed by lecuine, and inhibited by 2-keto-isovarlerate and its end product, tyrosine. 2-ketoisocaproate can not be introduced if 2-keto-isovarlerate inhibit TyrB and IlvE is absent.
References
Leucine Biosynthesis References
Wessler SR, Calvo JM: Control of leu operon expression in Escherichia coli by a transcription attenuation mechanism. J Mol Biol. 1981 Jul 15;149(4):579-97.
Pubmed: 6171647
Powell JT, Morrison JF: Role of the Escherichia coli aromatic amino acid aminotransferase in leucine biosynthesis. J Bacteriol. 1978 Oct;136(1):1-4.
Pubmed: 361681
Highlighted elements will appear in red.
Highlight Compounds
Highlight Proteins
Enter relative concentration values (without units). Elements will be highlighted in a color gradient where red = lowest concentration and green = highest concentration. For the best results, view the pathway in Black and White.
Visualize Compound Data
Visualize Protein Data
Settings