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CHARACTERISTICS AND PRODUCTS OF A CELL‐FREE POLYPEPTIDE SYNTHESIZING SYSTEM FROM NEONATAL AND ADULT MOUSE BRAIN
Author(s) -
Gilbert B. E.,
Grove Barbara K.,
Johnson T. C.
Publication year - 1972
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1972.tb03821.x
Subject(s) - ribosome , protein biosynthesis , ribosomal rna , transfer rna , phenylalanine , biochemistry , biology , translation (biology) , cell free system , chromosomal translocation , rna , messenger rna , amino acid , in vitro , gene
—The regulation of protein synthesis by ribosomes isolated from mouse brain tissue was studied using a cell‐free polyphenylalanine synthesizing system. Polypeptide synthesis was followed by assaying translocation and analysing the reaction products by BD‐cellulose chromatography. The brain ribosomal activity could be divided by these methods into two distinct steps : binding of aminoacyl‐tRNA to the ribosome and active translocation leading to subsequent polyphenylalanine synthesis. In comparison to initial binding of aminoacyl‐tRNA, translocation in the cell‐free system increased the incorporation of labelled phenylalanine by 10‐fold. An analysis of the reaction products clearly showed active ribosomal synthesis of oligophenylalanine from [ 3 H]phe‐tRNA. Ribosomes isolated from neonatal brain tissue were 2–4 times as active as those obtained from adult brain tissue in polypeptide synthesis. In addition, polypeptides synthesized on the more active ribosomes from neonates tended to be of greater chain length than those from adult. Therefore, the maturation‐dependent decrease in ribosomal protein synthetic activity during neural development was shown to be directly associated with the ribosome particles.