<prompt> A reactant generated by neutrophils that plays an impoant role in bacterial killing isNADPH oxidaseHexose monophosphate shuntG proteinsSuperoxide anion  <response>: Superoxide anion is generated when oxygen is reduced by cytoplasmic NADPH. The reduction is carried out by the enzyme NADPH oxidase, which is not a reactant but a catalyst activated in cells responding to bacteria. 