Studies on the initiation of protein synthesis in mouse myeloma tumors
| Autor: | George H. Jones |
|---|---|
| Rok vydání: | 1975 |
| Předmět: |
Biophysics
Biology Immunoglobulin light chain Biochemistry Ribosome Cell Line chemistry.chemical_compound Mice Methionine Biosynthesis Protein biosynthesis Animals Amino Acids Molecular Biology chemistry.chemical_classification Mice Inbred BALB C Metabolism Neoplasms Experimental Molecular biology Amino acid Neoplasm Proteins N-terminus chemistry Protein Biosynthesis Multiple Myeloma |
| Zdroj: | Archives of biochemistry and biophysics. 170(2) |
| ISSN: | 0003-9861 |
| Popis: | 35 S- and 3 H-labeled short, nascent peptides have been extracted from mouse myeloma ribosomes after incubation of myeloma fragments with [ 35 S]methionine and [ 3 H]amino acids. Edman analysis of these peptides reveals that most of the methionine is present at the N terminus but that other N-terminal amino acids are also present. Light chains synthesized by the RPC-20 tumor fragments were purified from ribosomes, cell sap (released light chain) and the incubation medium (secreted light chain). Ribosome-bound light chains were found to possess some N-terminal methionine whereas released and secreted light chains did not. Since methionine is not the N-terminal amino acid of light (L) chains purified from the urine of tumor-bearing mice, the results indicate that methionine initiates L chain biosynthesis in the myeloma. Total nascent 35 S-labeled peptides were extracted from myeloma ribosomes and fractionated on Sephadex G-50. Edman analysis of Chromatographic fractions of varying sizes indicated that the percentage of N-terminal methionine decreased with increasing chain length. This behavior is expected if methionine serves as an initiator amino acid but is removed before completion of the polypeptide chain on the ribosome. |
| Databáze: | OpenAIRE |
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