title: Incorporation of L-tyrosine, L-phenylalanine and L-3,4-dihydroxyphenylalanine as single units into rat brain tubulin.
abstract: The product of the incorporation of [14C]tyrosine as single unit into a protein of the soluble fraction of rat brain homogenate was purified by following a procedure used to purify tubulin. Sodium dodecylsulphate-polyacrylamide gel electrophoresis of the purified material showed a single protein band containing all the radioactivity. Purification data indicate that this protein accounts for 10.2% of the total protein of the supernatant fraction. This is in good agreement with the amount found for tubulin by the [3H]colchicine-binding method (10.5% of the total protein). The incorporated [14C]-tyrosine was found in the alpha-subunit of tubulin. Protein labelled with [3H]colchicine and [14C]tyrosine was precipatated with vinblastine sulphate and the radioactivity of 3H and that of 14C were quantitatively recovered in the precipitate (98%). Sodium dodecylsulphate-polyacrylamide gel electrophoresis of the vinblastine precipitate showed that the 14C radioactivity moved with the tubulin band. Results obtained in experiments with phenylalanine and 3,4-dihydroxyphenylalanine were identical to those obtained for tyrosine. Bineing of colchicine did not interfere with the incorporation of tyrosine. About 30% of tubulin from rat brain supernatant fraction can incorporate tyrosine as single unit.
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D003078:Colchicine / Q000378:metabolism; D004295:Dihydroxyphenylalanine / Q000378:metabolism*; D006023:Glycoproteins / Q000096:biosynthesis*; D010649:Phenylalanine / Q000378:metabolism*; D051381:Rats; D011955:Receptors, Drug; D014404:Tubulin / Q000096:biosynthesis*; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D006023:Glycoproteins; D011955:Receptors, Drug; D014404:Tubulin; D014443:Tyrosine; D010649:Phenylalanine; D004295:Dihydroxyphenylalanine; D003078:Colchicine