Mix flour, 1/4 teaspoon salt and 1/4 teaspoon pepper. Cut each tenderloin crosswise in half; pound each piece with a meat mallet to 3/4-in. thickness. Toss with flour mixture; shake off excess.
In a large nonstick skillet, heat oil over medium heat. Add turkey; cook until a thermometer reads 165°, 6-8 minutes per side. Remove from pan; keep warm.
In same skillet, heat butter over medium-high heat; saute mushrooms until tender, 3-4 minutes. Stir in broth and wine. Bring to a boil, stirring to loosen browned bits from pan; cook until liquid is reduced by half, 10-12 minutes. Stir in lemon juice and the remaining salt and pepper. Serve with turkey.