EFFECT OF PHENYLALANINE AND ALPHA-METHYLPHENYLALANINE ON IN-VITRO INCORPORATION OF P-32 INTO CYTOSKELETAL CEREBRAL PROTEINS

We studied the effects of L-phenylalanine and alpha-methylphenylalanin e on P-32 in vitro incorporation into cytoskeletal proteins from cereb ral cortex of 17-day-old rats. Slices of cerebral cortex were incubate d in the absence or presence of increasing concentrations of L-phenyla lanine, alpha-methylphenylalanine or L-phenylalanine plus alpha-methyl phenylalanine for 1 h. The cytoskeletal fraction obtained from slices was incubated in the presence of the same drugs and the P-32 in vitro incorporation into cytoskeletal proteins was measured. Addition of alp ha-methylphenylalanine did not change P-32 in vitro incorporation into the cytoskeletal proteins, but phenylalanine decreased the in vitro p hosphorylation of beta tubulin. Furthermore, addition of L-phenylalani ne plus alpha-methylphenylalanine decreased the in vitro phosphorylati on of both 160 kDa neurofilaments and alpha-tubulin.