Bifunctional enzyme that possesses chorismate synthase and intrinsic flavin reductase activity, it uses NADPH to reduce FMN. 5-O-(1-carboxyvinyl)-3-phosphoshikimate = chorismate + phosphate Metabolic intermediate biosynthesis; chorismate biosynthesis; chorismate from D-erythrose 4-phosphate and phosphoenolpyruvate: step 7/7. Belongs to the chorismate synthase family.