Figure 1.

Descriptions of two possible origins of the stretched exponential kinetics in the one-time autocorrelation of the fluorescence intensity as observed in ref. 5. The schemes in A and B are two special cases of the Grand scheme in ref. 5. In A, there are a number of intermediate states (E_k, k = 1,2,3,… ,n) that the enzyme may traverse before a new product is formed (EP). In B, transitions to the EP state are exponential for each substrate turnover; however, each turnover may occur via any of the n channels, each with a different state transition probability.