Although transition states were localized for all reactions within the uncatalyzed rTCA cycle, these reactions are not all kinetically favored. Competing b2f2 pathways that were explored show lower activation barriers than many of the main cycle reactions. The dehydration of malate (S2) that yields fumarate (S3) has several competing reaction channels with barriers of 23.4 kcal⸱mol -1 (R3) and 18.0 kcal⸱mol -1 (R4), substantially lower than the main cycle barrier of 35.0 kcal⸱mol -1 (R2). This pattern continues throughout the cycle. In the conversion of succinate (S4) to 2-oxoglutarate (S7), the carboxylation step (R8) competes with alternative pathways showing barriers as low as 53.9 kcal⸱mol -1 (R14). Similarly, the carboxylation of 2-oxoglutarate (S7) to isocitrate (S9) faces competing pathways with barriers as low as 43.1 kcal⸱mol -1 (R16). The isomerization of isocitrate (S9) to citrate (S11) proceeds through dehydration and hydration steps, where the dehydration step (R18) with a barrier of 42.2 kcal⸱mol -1 competes with pathways as low as 31.9 kcal⸱mol -1 (R20).