Except as prohibited by the Constitution and laws of the United States, all property owned or possessed in this state by a corporation organized under the laws of the United States or owned or possessed by an agency of the United States engaged in this state in proprietary, as distinguished from governmental, activities shall be subject to ad valorem taxation in this state at the same rate and in the same manner as the property of private corporations owning property in this state and engaged in similar businesses. All laws relating to ad valorem taxation of private corporations shall apply to ad valorem taxation of agencies of the United States and corporations organized under the laws of the United States.