Dear Sir. Concerning your issue about the chemical or biochemical method to detect 2-ketoisovalerate. The identification, purification, and characterization of the a-ketoisovalerate decarboxylase from Lactococcus lactis, a novel enzyme responsible for the decarboxylation into aldehydes of a-keto acids derived from amino acid transamination. The kivd gene consisted of a 1647 bp open reading frame encoding a putative peptide of 61 kDa. Analysis of the deduced amino acid sequence indicated that the enzyme is a non-oxidative thiamin diphosphate (ThDP)-dependent aketo acid decarboxylase included in the pyruvate decarboxylase group of enzymes. The active enzyme is a homo-tetramer that showed optimum activity at 45 C and at pH 6.5 and exhibited an inhibition pattern typical for metal-dependant enzymes. In addition to Mg2+, activity was observed in presence of other divalent cations such as Ca2+, Co2+ and Mn2+. The enzyme showed the highest specific activity (80.7 U mg1 ) for a-ketoisovalerate, an intermediate metabolite in valine and leucine biosynthesis. On the other side, decarboxylation of indole-3-pyruvate and pyruvate only could be detected by a 100-fold increase in the enzyme concentration present in the reaction. I think the following below link and the attached file may help you in your analysis:

http://onlinelibrary.wiley.com/doi/10.1111/j.1574-6968.2004.tb09778.x/pdf https://bmcbiotechnol.biomedcentral.com/articles/10.1186/1472-6750-12-55

Thanks

Here is a listing of enzyme reactions in which 2-ketoisovalerate has been reported to be a substrate:

http://brenda-enzymes.org/ligand.php?brenda_ligand_id=3591

If you can obtain or prepare one of these enzymes, and the reaction produces a detectable absorbance or fluorescence change, then you might be able to use the reaction as an assay for 2-ketoisovalerate. Isam Eldin Hussein Elgailani gave one suggestion already. The easiest method would involve a NAD(P)NAD(P)H interconversion, which is measurable as an absorbance change at 340 nm.

Thankyou Adam B Shapiro and Isam Eldin Hussein Elgailani for your useful suggestions.

please look in

www.rsc.org/journals-books-databases/about-journals/analytical-methods