Figure 1

Turnover of LA and 13-HOD by glyoxysomes from etiolated cucumber (A/B) or sunflower (C/D) in the optical β-oxidation assay. The figures show one typical experiment while the mean values for all experiments are given in Table 1. A/C: Initial rates for NADH-formation from different fatty acid concentrations were fitted according to a hyperbolic equation. Comparable rates of NADH-formation and S_0.5 values for turnover of 13-HOD by glyoxysomes from cucumber (A) or sunflower (C) are observed, but only weak rates of NADH-formation from LA by sunflower organelles can be detected. B/D: The final concentrations of NADH were calculated from the final absorbance at 340 nm and the formed molecules NADH from each molecule of fatty acid was obtained from the slope of a linear fit. Either all data points or only the concentrations up to 5 μM were used for the fitting procedure. The latter value is less influenced by inactivation effects and is thought to give a more precise result. Again, comparable values for turnover of 13-HOD are obtained for both plants, but NADH formation from LA is strongly decreased when sunflower glyoxysomes are used.