The role of phenylalanine in structure-function relationships of phenylalanine hydroxylase revealed by radiation target analysis

摘要

The activity of rat liver phenylalanine hy- droxylase (PAH; phenylalanine 4-monooxygenase, EC 1.14.16.1) is regulated by interaction with its substrate, phe- nylalanine, and its coenzyme, BH4 [tetrahydrobiopterin (6R- dihydroxypropyl-L-erythro-5,6,7,8-tetrahydropterin)]. The structural changes accompanying these interactions have been studied by radiation target analysis. PAH purified from rat liver was incubated with 2 mM phenylalanine to achieve complete activation of the enzyme.