Figure 7.

a, b, The effect of free [Ca²⁺] on the H₂O₂ (a) and NADH formation (b) measured with isolated α-KGDH. Isolated α-KGDH was incubated in a buffer containing different concentrations of ionized Ca²⁺ (0-100 μm). Ca²⁺ concentrations were controlled as described in Materials and Methods. The experimental protocol was as described for Figure 3, but ADP and Mg²⁺ were not present in the medium. H₂O₂ formation was measured in the absence (•) or presence (○) of NAD⁺ (1 mm). Values represent mean ± SEM from three experiments. Asterisk indicates points significantly different from the control (measured in the absence of Ca²⁺).