The relative intensities of UppP-bound C55-PP and C55-P as a function of time. For this analysis, only the binding of one substrate or one product molecule is considered. Data points are represented by circles; error bars are standard deviations of three replicate measurements. Lines are exponential fit, yielding apparent rate constants 0.090 0.008 min-1and 0.069 0.004 min-1for C55-PP and C55-P, respectively.