Okla. Stat. tit. 46, § 46-10: Separate instrument recorded

Every instrument explanatory of any deed or other writing

purporting to be a conveyance but intended to be defeasible or as

security for the payment of money, shall be deemed a part thereof,

and must be filed and recorded therewith; and unless such

instruments are so filed and recorded together, they and each of

them shall have no other effect than an unrecorded mortgage, and the

recording of the principal instrument shall secure no rights to the

holder thereof.