Protein synthesis in the cotyledons of Pisum sativum L. Protein factors involved in the binding of phenylalanyl-transfer ribonucleic acid to ribosomes.
1. Proteinaceous factors contained in a 0.5m-KCl extract of ribosomes from pea cotyledons form a ternary complex at 0 degrees C with [(14)C]phenylalanyl-tRNA and poly(U). The complex is measured by its quantitative retention on Millipore filters. 2. Complex-assembly is optimal at 5mm-Mg(2+) and is independent of GTP and ribosomes. 3. The addition of ribosomes is required to stabilize the complex at 34 degrees C. The complex binds to a puromycin-sensitive site on the ribosome. 4. Soluble factors from the 250000g supernatant of pea cotyledon form a Millipore-retainable complex dependent on GTP and ribosomes. 5. Complex-formation by soluble factors has a Mg(2+) optimum of 10-12mm and forms a puromycin-insensitive complex with ribosomes. 6. The function of the ribosomal protein factors and the supernatant fraction in initiation of protein synthesis is discussed.
D001665:Binding Sites; D002499:Centrifugation, Density Gradient; D006160:Guanosine Triphosphate / Q000378:metabolism; D007700:Kinetics; D046911:Macromolecular Substances; D008274:Magnesium / Q000494:pharmacology; D010649:Phenylalanine / Q000378:metabolism; D010940:Plant Proteins / Q000096:biosynthesis / Q000378:metabolism*; D010944:Plants / Q000378:metabolism*; D011189:Potassium Chloride; D011485:Protein Binding; D014176:Protein Biosynthesis / Q000187:drug effects; D011691:Puromycin / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism*; D011955:Receptors, Drug; D012270:Ribosomes / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors; D046249:Transfer RNA Aminoacylation
D046911:Macromolecular Substances; D010940:Plant Proteins; D011955:Receptors, Drug; D010649:Phenylalanine; D011691:Puromycin; D011189:Potassium Chloride; D006160:Guanosine Triphosphate; D012343:RNA, Transfer; D008274:Magnesium