3-methyl-2-oxovaleric acid is a 2-oxo monocarboxylic acid that is valeric acid carrying oxo- and methyl substituents at C-2 and C-3, respectively. An alpha-keto acid analogue and metabolite of isoleucine in man, animals and bacteria. Used as a clinical marker for maple syrup urine disease (MSUD). It has a role as a human metabolite. It derives from a valeric acid. It is a conjugate acid of a 3-methyl-2-oxovalerate. **NMR note.** often overlap with [Butyric acid](../171/) Experimental spectrum in Natural Products Magnetic Resonance Database: [NP0000199](https://np-mrd.org/spectra/nmr_one_d/1392)