细菌与氧 Aerobes and anaerobes Oxygen requirement: terminal oxidase High-affinity oxidase: microxic/anoxic respiration Low-affinity oxidase: oXic respiration Oxygen tolerance: reactive oxygen species(ROs) ROs:O2+e→O2 SoD:22+2H→>H2O2+O2, Catalase:2H2O2→ 2H20+O2 ROs> DNA and protein damage repair细菌与氧 9 • Aerobes and anaerobes • Oxygen requirement: terminal oxidase • High-affinity oxidase: microxic/nanoxic respiration • Low-affinity oxidase: oxic respiration • Oxygen tolerance: reactive oxygen species (ROS) • ROS: O2 + e  O2 -… • SOD: 2O2 - + 2H+  H2O2 + O2 , Catalase: 2H2O2  2H2O + O2 • ROS  DNA and protein damage repair