<prompt> All of the following are characteristics of phenylalanine hydroxylase, EXCEPTMixed function oxidaseTetrahydrobiopterin is a cofactorNADPH provides the reducing powerVitamin C is a cofactor  <response>: PAH is a mixed-function oxidase because it incorporates one atom of oxygen into phenylalanine and another atom of oxygen into H2 to form H2O. Remember: Not all hydroxylase enzymes require Vitamin C. Not all carboxylase enzymes require Vitamin K. 