Valine

L-Valine

Abbreviated: Val or V

Molecular Formula: C₅H₁₁NO₂

pKa: 2.32 (-COOH), 9.62 (α-NH₂)

Physiological roles:

• It is a branched and non-polar (hydrophobic).
• The second to last product in the synthesis of Valine leads to the production of L-Leucine. 
• Valine is important in the natural production of Penicillin by mold.

 

Valine-Penicillin

To learn more about the role of Valine in the biosynthesis of penicillin and cephalosporin read the article entitled The Role of Valine in the Biosynthesis of Penicillin N and Cephalosporin C by a Cephalosporium sp found at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1270495/

 Synthesis:

Synthesis of Valine

Beginning with the combination of two pyruvate molecules and the help of the enzyme Acetohydroxy acid synthase we will form the product α-Acetolactate. Second, we have the oxidation of NADPH with the enzyme Acetohydroxy acid Isomeroreductase to form the product α,β-Dihydroxy isovalerate. Third, with the loss of water and the enzyme Dihydroxy acid dehydrase we form the product α-Keto isovalerate. For the last reaction we have an addition of glutamate and with the enzyme Branched-chain amino acid glutamate transaminase we will get the product of L-Valine and α-ketoglutarate. The above picture is a simplified representation of this and it shows that the formation of Isoleucine and Valine share the same enzymes for their last four reactions.