<prompt> Malonate competitively inhibitsFumarate dehydrogenaseSuccinate dehydrogenaseAconitaseSuccinate thiokinase  <response>: Inhibitors of TCA Cycle - A. Aconitase citrate to aconitate is inhibited by fluoro-acetate. This is non-competitive inhibition. B. Alpha ketoglutarate dehydrogenase alpha ketoglutarate to succinyl CoA is inhibited by Arsenite. This again is non-competitive inhibition. C. Succinate dehydrogenase succinate to fumarate is inhibited by malonate; this is competitive inhibition. competitive inhibition - In competitive inhibition, the inhibitor will be a structural analog of the substrate. There will be similarity in three dimensional structure between substrate S and inhibitor I. For example, the succinate dehydrogenase reaction is inhibited by malonate. Competitive inhibition is usually reversible. Or, excess substrate abolishes the inhibition. REF:DM VASUDEVAN TEXTBOOK OF BIOCHEMISTRY,EIGHTH EDITION,PG.NO.,309,63. 