Characterization of Energy-Dependent Phosphate Uptake by Blue-Green Alga Anacystis Nidulans: Adaptation to External Phosphate Levels Obeys a Linear Flow-Force Relation

Abstract

The incorporation of phosphate by the blue-green alga Anacystis nidulans proceeds against the potential difference between the external phosphate concentration [Pe] and the internal polyphosphate pool, i.e. 2.3RT1og(K[P_e]) (K=¹⁰⁻⁵ M⁻¹ represents the equilibrium constant of polyphosphate formation under the external conditions). The energy 2.3RTΔpH that drives this process originates, in the light, from photophosphorylation (ΔpH is the pH-gradient across the thylakoid membrane). Near equilibrium the uptake rate can be assumed to be proportional to the overall affinity of polyphosphate formation¹,

$$ {J_P} = {L_p}[\log (K[{P_e}]) + {q^2}{n_p}\Delta pH] . $$

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