Effect of hyperphenylalaninemia chemically induced on in vitro incorporation of 32P into cytoskeletal proteins from cerebral cortex of developing rats.
We studied the effect of hyperphenylalaninemia on in vitro incorporation of 32P into cytoskeletal proteins from cerebral cortex of rats by injecting l-phenylalanine plus alpha-methylphenylalanine subcutaneously from the 6th to the 14th day postpartum. Chronic hyperphenylalaninemia induced an increased in vitro phosphorylation of the 150-kDa neurofilament subunit and tubulins present in the cytoskeletal fraction at the end of the treatment and 3 days after treatment discontinuation. In addition, when in vitro phosphorylation of the cytoskeletal proteins from treated animals was performed in the presence of the drugs we observed a decreased in vitro incorporation of 32P into these proteins. Thus, the effect of l-phenylalanine plus alpha-methylphenylalanine on the endogenous protein kinase and phosphatase activities was examined and the results demonstrated that these drugs have an inhibitory effect on calcium/calmodulin-dependent protein kinase II and protein phosphatase type 1.
de Freitas
M S
MS
Departamento de Bioquímica, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre RS, Brazil.
de Mattos-Dutra
A
A
Schroder
N
N
Wannmacher
C M
CM
Pessoa-Pureur
R
R
D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000187:drug effects*; D002540:Cerebral Cortex / Q000187:drug effects*; D003599:Cytoskeleton / Q000187:drug effects*; D066298:In Vitro Techniques; D010649:Phenylalanine / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar
D010649:Phenylalanine; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases