Northrop notation

Kinetic complexity definition, 43 Klinman s approach, 46 Kinetic isotope effects, 28 for 2,4,6-collidine, 31 a-secondary, 35 and coupled motion, 35, 40 in enzyme-catalyzed reactions, 35 as indicators of quantum tunneling, 70 in multistep enzymatic reactions, 44-45 normal temperature dependence, 37 Northrop notation, 45 Northrop s method of calculation, 55 rule of geometric mean, 36 secondary effects and transition state, 37 semiclassical treatment for hydrogen transfer,... 

In describing isotope effects, we shall use the notation of Northrop (97), where leading superscripts identify the isotopic atom, with D, T, 13, 14, 15, 17, and 18 standing for deuterium, tritium, C, C, N, O, and 0. The isotope effect is the ratio of parameters for unlabeled and labeled species. Thus V is a deuterium isotope effect on V (i.e., Vh/Vd), and (V/K) is a C isotope effect on V/K. The same notation is used for equilibrium isotope effects, with Afeq being an N isotope effect on Afeq (i-e., Afeq >N/Afeq on). 

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