Valine (symbol Val or V) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group an α-carboxylic acid group (which is in the .Jun 13, 2005 A branched-chain essential amino acid that has stimulant activity. It promotes muscle growth and tissue repair. It is a precursor in the penicillin .Plant Physiol. 2017 Sep;175(1):51-61. doi: 10.1104/pp.17.00649. Epub 2017 Jul 13. 3-Hydroxyisobutyrate Dehydrogenase Is Involved in Both, Valine and .Valine is an aliphatic and extremely hydrophobic essential amino acid in humans related to leucine, Valine is found in many proteins, mostly in the interior.