Extended data Figure 9. Cadaverine can partially substitute for canonical polyamines, but only at non-physiologically high concentrations and at a certain pH, and does not protect S. cerevisiae against H₂O₂ stress.

a,b, Growth curves of Δspe1 strain depleted from spermidine grown in SM media alone or supplemented with 250 mM cadaverine in the absence (a) or presence of 0.1 mM spermidine (b). The data represent mean ± s.d.; n = 3 biologically independent samples. c, Growth curves showing the effect of lysine supplementation on wild-type and Δspe1 strains carrying a control plasmid (empty) or overexpressing E. coli LdcC (LDC), when grown in SM media buffered or not buffered at pH 5.0. The data represent mean ± s.d.; n = 4 biologically independent samples per experiment. The experiment was repeated twice. d, H₂O₂ tolerances were determined as described above, but substituting lysine with 5 mM cadaverine. The data represent mean ± s.d.; n = 4 independent experiments. Even in the presence of this high level of cadaverine, the yeast cells to not tolerate higher levels of H₂O₂.