The polyamine-dependent modulation of phenylalanine hydroxylase phosphorylation state and enzymic activity in isolated liver cells.

ABSTRACT: The role of polyamines in the control of phenylalanine hydroxylase phosphorylation state and enzymic activity was investigated. Pre-treatment of liver cells with spermine (1 mM) abolishes the glucagon (1 nM)-stimulated increase in hydroxylase phosphorylation. Concurrently there is a decrease in phenylalanine hydroxylation flux, reflecting decreased enzyme activity; 50% inhibition occurs at approx. 10 microM-spermine. These results are discussed in the context of reports concerning the properties of protein phosphatase 2A.

SUBMITTER: Fisher MJ 

PROVIDER: S-EPMC1146977 | biostudies-other | 1986 Jul

REPOSITORIES: biostudies-other