BCKDK and obesity due to melanocortin 4 receptor deficiency: Furthermore, overnutrition, particularly diets high in fructose, induce the expression of the hepatic transcription factor ChREBP-β by which, levels of the BCKDK are increased and those of PP2Cm decreased, leading to elevated BCKDK:PP2Cm ratio and inhibition of the activity of the BCKD complex, contributing to the obesity-related rise in plasma BCAAs and BCKAs [45] (Figure 5).