Section 190.1 - Authority, purpose, and scope(a)Authority. This part contains regulations issued under section 501 of the Depository Institutions Deregulation and Monetary Control Act of 1980, Public Law 96-221 , 94 Stat. 161.(b)Purpose and scope. The purpose of this permanent preemption of state interest-rate ceilings applicable to Federally-related residential mortgage loans is to ensure that the availability of such loans is not impeded in states having restrictive interest limitations. This part applies to loans, mortgages, credit sales, and advances, secured by first liens on residential real property, stock in residential cooperative housing corporations, or residential manufactured homes as defined in § 190.2 of this part.