2.3- dihydroxy-isovalerate

Biosynthesis Leu is formed from pyruvic acid - 2-acetolactic acid [acetolactate synthase (EC 4.1.3.18.)+(l-hydroxyethyl)-TPP] - 2,3-dihydroxy-isovaleric acid [reductase+NAD(P)H] - 2-oxoisova-leric acid [dihydroxyacid dehydratase] - 2-isopropyl-malate [2-isopropylmalate synthase + acetyl-CoA (EC 4.1.3.12)] -> 3-isopropylmalate [isopropylmalate dehydratase (EC 4.2.1.33) -HjO+HiO] 2-oxo-isocaproate [3-isopropylmalate dehydrogenase (EC 1.1.1.85) + NAD ] L. [leucine aminotransferase (EC... 

Methyl 3,6-epidioxy-6-methoxy-4,14,16-octadecatrienoate, in E-60008 Pulchellin 2-0-isovalerate, in P-80189 Sterebin B, in S-60052 Sterebin C, in S-60052 Tetradecahydro-4,6-dihydroxy-9,9,12a-trimethyl-6/ -phenanthro[l, 10a-c]furan-3-carboxylic acid, T-60038 e /-3)9,4a,l 6< -Trihydroxy-13-cleroden-15,16-olide, in D-80303... 

Fio. 7. Scheme of biosynthesis of valine and isoleucine. R tepresents a methyl group in valine and an ethyl group in isoleucine biosynthesis. I is pyruvate or a-keto-butyrate II is a-acetolactate or a-aceto-a-hydroxybutyrate HI is a-keto-/3-hydroxy> isovalerate or a-keto- -hydroxy- S-metbylvalerate IV is a,/ -dihydroxyisovalerate or a-0-dihydroxy- -methylvalerate V is a-ketoisovalerate or a-keto-d-methylvalerate and VI is valine or isoleucine. 

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