title: Yeast protein synthesis. Preparation and analysis of a highly active cell-free system.
abstract: A detailed description is given of the techniques for preparing, handling and assaying a cell-free protein-synthesizing system from yeast, analogous to crude (S-30) Escherichia coli extracts. Its basic characteristics are described. The rate of poly(U)-directed polyphenylalanine synthesis was at least fivefold higher than in previously reported yeast cell-free systems, approaching that of crude mammalian cell-free systems. Fractionation of the S-30 extracts lowered activity. Organelles and their fragments present in the S-30 extract neither contributed to nor inhibited cytoplasmic protein synthesis. There was a component localized in the high-speed supernatant that caused an inhibition of polyphenylalanine synthesis. Poly(U) programmed the synthesis of long-chain polyphenylalanine, in contrast with the only other yeast system in which this has been examined (Bretthauer & Golichowski, 1968). Preincubation techniques inactivated the system and probably a small proportion only of the ribosomes was active.
mesh_terms: D002458:Cell Fractionation / Q000379:methods; D002474:Cell-Free System; D005656:Fungal Proteins / Q000096:biosynthesis*; D007700:Kinetics; D010452:Peptide Biosynthesis; D010649:Phenylalanine / Q000378:metabolism; D011119:Polynucleotides / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D013347:Subcellular Fractions; D013696:Temperature
chemical_list: D005656:Fungal Proteins; D011119:Polynucleotides; D010649:Phenylalanine