Effects of quinones on the production of H2O2 by LacVP-mycelium (A) and Lac-mycelium (B) from P. eryngii. Mycelia were incubated in 50 ml 20 mM phosphate buffer, pH 5, in the absence (No Q) and presence of 500 μM BQ, MBQ, DBQ, or MD. Incubations with 500 μM H2O2 were also carried out in the absence of quinones. The error bars indicate standard deviations.