Y Hydroxybutyrate dehydrogenase

Relkin N and Nelson T. Regulation and. properties of an NADP+ oxidoreductase which functions as a. y-hydroxybutyrate dehydrogenase. J Neurochem, 1983, 40, 1639. 

Figure 34-32 Metabolism of y-hydroxybutyrate and its precursors. /, alcohol dehydrogenase 2, aldehyde dehydrogenase 3, lactonase 4, GHB dehydrogenase J, SSA reductase 6, GABA transaminase 7, glutamate decarboxylase 8, SSA dehydrogenase.

Figure 12-4. Gamma-aminobutyric acid metabolic interactions. GA = glutaminase GABA = y-aminobutyric acid GABA-T = GABA a-oxaloglutarate transaminase GAD = glutamic acid decarboxylase GS = glutamic synthetase NAD+ = nicotinamide adenine dinucleotide PP = pyridoxal phosphate (vitamin B6) SSA = succinic semialdehyde SSADH = succinic semialdehyde dehydrogenase GHB = y-hydroxybutyric acid GBL = y-butyrolactone.

Fig. 11 Biotechnological approaches for the production of y-valerolactone (y-VL) from levulrnic acid. The key step is the bioreduction of levulinic acid 4-hydroxyvalerate (4-VL), which subsequently can lactonize to y-VL. (a) Biotransformation using Pseudomonas putida whole-cell overexpression of thioesterase tesB and paraoxonase I PONl (Martin et al. 2010). (b) A new variant of 3-hydroxybutyrate dehydrogenase 3HBDH from Alcaligenes faecalis catalyzes the bioreduction of levulinic acid to 4-hydroxyvalerate (4-HV) (Yeon et al. 2013). (c) Chemoenzymatic route using carbonyl reductase from Candida parapsilosis CPCR2 and lipase B CAL-B from Candida antarctica (Gotz et al. 2013)...

Yeon YJ, Park H-Y, Yoo YJ (2013) Enzymatic reduction of levulinic acid by engineering the substrate specificity of 3-hydroxybutyrate dehydrogenase. Bioresour Technol 137 377-380 Zanghellini AL (2012) Fermentation route for the production of levulinic acid, levulinate esters, valerolactone, and derivatives thereof. World patent No 2012030860A1... 

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