The branched-chain alpha-ketoacid dehydrogenase (BCKDH) complex occupies a strategic point in the branched-chain amino acid (BCAA) catabolic pathway, and careful regulation of its activity is essential for correct BCAA metabolism. The overall activity of the BCKDH complex is controlled by the phosphorylation (inactivation)/dephosphorylation (activation) cycle. Mitochondrial protein phosphatase 1K (PPM1K) dephosphorylates the E1 beta subunit of BCKDH therby regaining its active state. PPM1K requires Mn2+ as a cofactor for phosphatase activity (Wynn et al. 2012).