Fig. 3.

A Release pattern of molecular oxygen (O₂) measured polarographically following successive light flashes of spinach thylakoids at 4 °C (Messinger and Renger 2008). Note that O₂ release follows a 4-flash pattern (the starting dark stable state is S₁). The original experiment was performed by Pierre Joliot as early as 1969 (Joliot et al. 1969). B Water oxidation cycle (Kok cycle) (Kok et al. 1970) detailing the five basic S states (S₀ to S₄), the light-induced 1e⁻ oxidation steps and the proton release pattern (Dau and Haumann 2008), the uptake of the two substrate waters (Hillier and Wydrzynski 2008) and the Mn oxidation states (Krewald et al. 2015) (vide infra). The reaction times for the single electron oxidation steps are also indicated (Klauss et al. 2012a). Note that here the “S” stands for “state” and not for the electron spin quantum number S