FIG. 6.

Effect of KOCN on CO₂ transport. S. elongatus PCC7942 cynA mutant cells grown under low-C_i conditions were placed in the reaction chamber attached to the MS and allowed to equilibrate (25 mM BTP-HCl buffer, pH 8, at 30°C) in the light (300 μmol of photons m⁻² s⁻¹) in the presence of KOCN. CO₂ transport was initiated by adding 3.5 μM CO₂ to the reaction vessel, and its concentration was followed over time. The difference between the curves obtained in the light (A, 0 mM KOCN, maximum uptake) and the dark (F, no uptake) was taken as a measure of CO₂ transport. The effect of 1, 3, 5, or 10 mM KOCN (B, C, D, and E) on CO₂ transport are also shown.