description
General Background : VAL is one of the three main branched chain amino acids (BCAAs), along with : LEU and : ILE. The catabolic pathways of the BCAAs can be divided into two sequential series of reactions, referred to as the common pathway and the distal pathway. The common pathway includes three enzymes that catalyze the conversion of all three BCAAs to their respective acyl-CoA derivatives (:METHACRYLYL-COA, :3-METHYL-CROTONYL-COA, and : CPD-1083 for :VAL, :LEU, and :ILE, respectively), though the intermediates formed by these enzymes are different for the different amino acids. The distal parts of the pathway are completely different for the three BCAAs, and comprise enzymes specific for each amino acid. About this Pathway The catabolism of : VAL involves its conversion via :2-KETO-ISOVALERATE to : ISOBUTYRYL-COA by the L-valine aminotransferases . The : ISOBUTYRYL-COA is then desaturated to form the alpha,beta-unsaturated thioester : METHACRYLYL-COA catalyzed by the : CPLX-7050 . Hydration to :3-HYDROXY-ISOBUTYRYL-COA and thioester hydrolysis forms the diffusible and transportable compound :3-HYDROXY-ISOBUTYRATE. In most tissues, : 3-HYDROXY-ISOBUTYRATE is oxidized to : CH3-MALONATE-S-ALD. However, it can be released into the blood stream from some tissues and serve as a substrate for hepatic gluconeogenesis . The pathway spans both the cytoplasmic and mitochondrial compartments. The first reaction takes place in the cytoplasm, and the product : 2-KETO-ISOVALERATE is then transported into the mitochondria, where the remaining reactions occur

external resources
NCBI:142387
BIOCYC:HUMAN_VALDEG-PWY
PUBMED:10745006
PUBMED:3827880
PUBMED:6933702

genes
ABAT , BCAT1 , BCAT2 , BCKDHA , BCKDHB , DBT , DLD , ECHS1 , HADHA , ALDH6A1 , HIBCH , ACAD8 ,