A total of seven people had been on board the helicopter, including two Turkish crew, when it crashed shortly after taking off from Istanbul's Ataturk airport.
Bulent Eczabicasi, speaking to reporters, did not specify who the five dead people were or who had survived.An official of Kugu Havacilik, a company involved in issuing the licence for the helicopter, told Reuters it belonged to the Eczacibasi pharmaceuticals and household products group.
The helicopter carrying high-level business executives crashed onto a Turkish highway, after it hit a television tower in an outlying district of Istanbul, NTV television reported.
The Sikorsky S-76 helicopter had taken off from Istanbul's main Ataturk airport with seven people on board.
CNN Turk quoted local officials as saying the seven included three Turks, two of them pilots, and four foreigners. The DHA agency said four Russians were in the helicopter.
Reporting by Tuvan Gumrukcu; Writing by Ralph Boulton; Editing by Gareth Jones