FIGURE 7.

Proposed network for regulation of the glucose oxidase system. Amplification of the H₂O₂ signal is achieved via a positive feedback loop. H₂O₂ induced oxidative modification of thiol groups in ROS sensitive regulatory proteins such as AnCF complex (Thön et al., 2010) or NapA (Marinho et al., 2014) leads to activation of goxC expression. Outside the cell an increase GOx activity may lead to a further increase in turnover of glucose in gluconic acid and H₂O₂. The increased extracellular H₂O₂ concentration is counterbalanced by H₂O₂ induced expression of the catR gene, leading to an extracellular catalase activity. Simultaneously, in a negative feedback loop, ROS activation of the thioredoxin system facilitates a return to the native state. GOx specific genes are indicated with an asterisk.