BIOL 155 |
| Many enzymes have flexible loops, which open to expose the substrate binding pocket and then close around a nonreacting phosphate group of the substrate so as to encapsulate the ligand at the active site. The binding interactions between the substrate phosphate group and such loops serve the mundane function of fixing the substrate at the enzyme active site. We have shown that these binding interactions also provide specific stabilization of the transition states for proton transfer catalyzed by triosephosphate isomerase (TIM) and decarboxylation catalyzed by orotidine 5'-monophosphate decarboxylase (OMPDC), because they are expressed in the absence of a covalent connection between the phosphodianion group and the reacting portion of the substrate. The specificity of dianion binding and the mechanism for the specific expression of the phosphate binding interactions at the transition state for these two enzyme-catalyzed reactions will be discussed. |
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Symposium in Honor of Perry Frey
2:00 PM-4:40 PM, Wednesday, August 22, 2007 BCEC -- 109A, Oral
Division of Biological Chemistry |