Figure 3. The Tetrahymena Ribozyme Reaction Pathway.

The ribozyme binds the oligonucleotide substrate (in two steps) and the exogenous G that serves as the nucleophile in the ribozyme reaction as described in the text ([33,56,57] and references therein). K ^G _d(E), K ^G _d(E·S)O, and K ^G _d(E·S)c are G dissociation constants from free E, (E·S)_O, and (E·S)_C, respectively. K ^IGS _d is the dissociation constant for the oligonucleotide substrate from the internal guide sequence, and K _dock and K′_dock are the docking equilibria for the E·S and E·S·G complexes, respectively. K ^S _d(E) and K ^S _d(E·G) are the observed dissociation constants for the oligonucleotide substrate from free E and the E·G complex, respectively, and k _chem is the observed rate of oligonucleotide substrate cleavage.