Energy storage in the photosynthetic electron-transport chain. An analogy with Michaelis-Menten kinetics

Abstract

Simultaneous measurements of fluorescence and thermal emission have been performed by applying combined fluorescence and photoacoustic techniques on isolated thylakoids pretreated by prolonged illumination with saturating light. The traces were used to create Lineweaver-Burk type plots, proving clearly at least a formal analogy between the kinetics of the mechanisms governing fluorescence and thermal emission from isolated thylakoids and Michaelis-Menten kinetics of enzymatic reactions. Two characteristic parameters were calculated from them (energy storage and half-saturation light intensity) in order to obtain a basic, initial response of the photosynthetic apparatus functioning under photoinhibition stress.