[13] Isotope effects: Determination of enzyme transition state structure

摘要: Publisher Summary Enzymologists wish to determine the transition state structures for enzymatic reactions several reasons: (1) compare mechanisms of and nonenzymatic in order understand better factors involved catalysis (2) “transition analogs” being used drugs, know what structure should be mimicked. Isotope effects have been many years study reactions. For reactions, observed isotope can reasonably interpreted once intrinsic values are known on chemical steps. The problem is that step (or steps) an reaction often not totally rate limiting, so one has either find a way make this limiting (by changing substrate, pH, or mutating enzyme) calculate effect. This chapter discusses some basic definitions, then describes more modern methods measuring determining effects. After that, it gives examples determination these studies tell about mechanisms.