1Mix all ingredients except beef and pita breads in shallow glass or plastic dish or resealable plastic food-storage bag. Add beef; turn to coat with marinade. Cover dish or seal bag and refrigerate at least 4 hours but no longer than 24 hours.
2Heat coals or gas grill. Remove beef from marinade; reserve marinade. Cover and grill beef 4 to 5 inches from medium heat 15 to 20 minutes, turning once and brushing frequently with marinade, until desired doneness. Discard any remaining marinade. Cut beef into thin slices. Serve in pita bread folds.