Developmental biochemistry of cottonseed embryogenesis and germination. Preferential charging of cotton chloroplastic transfer ribonucleic acid by Escherichia coli enzymes.
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Acylation↗
Biomedical subjects
W C Merrick
Publications and source records attributed to W C Merrick.
A ribosome dissociation factor from rabbit reticulocytes distinct from initiation factor M3.
A ribosome dissociation factor (DF), from a 0.5 M KCl wash fraction of rabbit-reticulocyte-ribosomes, has been purified by Sephadex G-200, phosphocellulose, DEAE-cellulose, and hydroxyapatite chromatography. The most purified preparation displayed one major and several minor bands on 3.75% acrylamide gels.DF cannot replace IF-M(1), IF-M(2A), IF-M(2B), IF-M(2), EF-1, or EF-2 in poly(U)-directed polyphenylalanine synthesis at low Mg(++) concentrations or in endogenous mRNA-directed globin synthesis. Conversely, these initiation and elongation factors showed little or no dissociation activity, even when assayed at levels 5-10 times greater than those required to saturate a polypeptide synthesis assay. Reticulocyte DF thus appears to be a distinct factor.
Animals↗
The developmental biochemistry of cotton seed embryogenesis and germination. IV. Levels of cytoplasmic and chloroplastic transfer ribonucleic acid species.
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Amino Acyl-tRNA Synthetases↗
Separation of reticulocyte initiation factor M 2 activity into two components.
IF-M(2), one of three initiation factors isolated by DEAE-cellulose chromatography from the 0.5 M KCl-wash fraction of rabbit reticulocyte ribosomes, has been separated by Sephadex G-200 chromatography into two components: IF-M(2A) and IF-M(2B). IF-M(2A) elutes near the void-volume, while IF-M(2B), which is much smaller in molecular weight than IF-M(2A), elutes slightly after a hemoglobin marker. In the presence of the other appropriate factors, both IF-M(2A) and IF-M(2B) are required to stimulate poly(U)-directed polyphenylalanine synthesis at low Mg(++) concentration, ApUpG-directed Met-tRNA(F) binding to washed reticulocyte ribosomes, and initiation of globin synthesis from endogenous mRNA. IF-M(2A) stimulates ribosome-dependent GTP hydrolysis, while IF-M(2B) does not; IF-M(2B) stimulates ApUpG-directed fMet-tRNA(F) binding in the presence of IF-M(1), while IF-M(2A) does not. Although IF-M(2A) and IF-M(2B) can be distinguished from each other by size and by activity, a distinct function for IF-M(2B) has not yet been found. Therefore, its precise role in the initiation process remains unclear.
Animals↗
Specific transformylation of one methionyl-tRNA from cotton seeding chloroplasts by endogenous and Escherichia coli transformylases.
Two isoaccepting chloroplastic and one cytoplasmic tRNA(Met) species have been separated from germinating cotton cotyledons. The methionylated form of one of the chloroplastic species (but none of the other or of the cytoplasmic tRNA(Met)) can be formylated either by an endogenous transformylase or by Escherichia coli transformylase.
Carbon Isotopes↗
Regulation of a protein synthesis initiation factor by adenovirus virus-associated RNA.
A small RNA accumulating late in adenovirus infection is required for efficient protein synthesis, although not specifically for the translation of viral proteins. This RNA maintains the activity of an initiation factor catalysing the earliest step of polypeptide chain initiation.
Antigens↗