Which of the following enzymes does the neutrophil use to initiate the production of toxic oxygen compounds that kill bacteria?
The first step in killing bacteria is the production of superoxide ion, O2- , by the action of NADPH oxidase on NADPH and O2. The superoxide is then conveed to hydrogen peroxide, either spontaneously or through the action of superoxide dismutase. The hydrogen peroxide can also be conveed to the toxic HOCl. radical by the action of myeloperoxidase. Note: Hydrogen peroxide is not an enzyme. Myeloperoxidase is pa of the killing pathway, but is active later in the sequence, when H2O2 is conveed in the presence of Cl- to the HOCl. radical. Superoxide is not an enzyme. Ref: Gallin J.I. (2012). Chapter 60. Disorders of Granulocytes and Monocytes. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.
Hydrogen peroxide
Myeloperoxidase
NADPH oxidase
Superoxide