In conclusion, we have demonstrated an alternate synthetic route to malonyl-CoA analogs where the thioester has been replaced with an ester or amide. These analogs were found to be generally stable over a 24-hour time course with FabH, a ketosynthase which performs acyl transfer and decarboxylative Claisen-condensation. Furthermore, while assessing substrate stability in the presence of FabH, we have revealed some interesting aspects of FabH catalysis, especially hysteresis. Previous reports of FabH reactivity with CoA disulfides revealed that there was likely a disordered conformation of FabH in the absence of acetyl-CoA along with negative cooperativity between the FabH active sites of the dimer, however the structural basis was not apparent in crystal structures. We expect careful examination of FabH catalysis with the UV-Vis assay used here and malonyl-S-ACP bound structures will reveal deeper insights into previously suggested FabH negative cooperativity. Furthermore, variation of wild-type and C112Q FabH activities as a function of pH poses further investigation. We anticipate that neutron diffraction experiments combined with substrate analogs will provide evidence for activation of FabH in the presence of substrate and knowledge of the protonation state of titratable residues critical to catalysis.