The experimental results on the interconversion of dihydroxyacetone phosphate and D-glyceraldehyde 3- phosphate catalyzed by triosephosphate isomerase that are presented in the previous five papers are here collected and analyzed according to the theory presented in the first paper The first paper in this series (Albery and Knowles, 1976a) presented the theory for 16 different experiments involving deuterium or tritium, which may be carried out on the system shown in Scheme I, where E is the enzyme, ES and EP are the