Acetylation of ribosome-associated proteins in vitro by an acetyltransferase bound to rat liver ribosomes

Biochemistry ◽  
1975 ◽  
Vol 14 (7) ◽  
pp. 1397-1403 ◽  
Author(s):  
Angel Pestana ◽  
Henry C. Pitot
Keyword(s):  
Rat Liver ◽  
Associated Proteins ◽  
Liver Ribosomes

scholarly journals Inhibition of protein synthesis in vitro by crotins and ricin. Effect on the steps of peptide chain elongation

1976 ◽  
Vol 156 (1) ◽  
pp. 7-13 ◽  
Author(s):  
S Sperti ◽  
L Montanaro ◽  
A Mattioli ◽  
G Testoni ◽  
F Stirpe
Keyword(s):  
Protein Synthesis ◽  
Rat Liver ◽  
Elongation Factor ◽  
Artemia Salina ◽  
Chain Elongation ◽  
Gtp Hydrolysis ◽  
Elongation Factor 2 ◽  
The Individual ◽  
Liver Ribosomes

The effects of crotin I and crotin II on the partial reactions of polypeptide chain elongation were investigated and compared with the known effects of ricin. Crotin II was a more powerful inhibitor than crotin I, but no qualitative differences between the two crotins were found. Rat liver ribosomes, preincubated with crotins and washed through sucrose gradients, remained inactive in protein synthesis. Among the individual steps of elongation, the peptidyltransferase reaction was unaffected by crotins, but some of the reactions that involve the interaction of elongation factors 1 and 2 with ribosomes were modified. A strong inhibition of the binding of elongation factor 2 to ribosomes and a stimulation of the elongation factor2-dependent GTP hydrolysis were observed; this indicates the formation of a very unstable elongation factor 2-GDP-ribosome complex, which, however, allows a single round of translocation to take place in the presence ofelongation factor 2 and added GTP. The elongation factor 1-dependent GTP hydrolysis was inhibited by crotins, whereas the enzymic binding of aminoacyl-tRNA, to both rat liver and Artemia salina ribosomes, was scarcely affected. In a protein-synthesizing system the inhibition by crotins and by ricin leads to a block of the nascent peptides on the ribosomal aminoacyl-tRNA site, an effect consistent with inhibition at the level of translocation. The mechanism of action of crotins appears to be very similar to that of ricin.

scholarly journals Inhibition by ricin of protein synthesis in vitro: 60S ribosomal subunit as the target of the toxin (Short Communication)

1973 ◽  
Vol 136 (3) ◽  
pp. 813-815 ◽  
Author(s):  
Simonetta Sperti ◽  
Lucio Montanaro ◽  
Alessandro Mattioli ◽  
Fiorenzo Stirpe
Keyword(s):  
Protein Synthesis ◽  
Rat Liver ◽  
Short Communication ◽  
Ribosomal Subunit ◽  
Site Of Action ◽  
Liver Ribosomes

Poly(U)-directed polyphenylalanine synthesis by rat liver ribosomes is strongly inhibited by ricin. Experiments involving hybridization between subunits derived from normal and ricin-treated ribosomes demonstrate that the 60S subunit is the site of action of the toxin. The toxin inactivates the 60S subunit independently of the presence of the 40S subunit.

scholarly journals Effect of cycloheximide on protein biosynthesis in rat liver

1966 ◽  
Vol 101 (3) ◽  
pp. 627-631 ◽  
Author(s):  
A Korner
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Mouse Liver ◽  
Species Differences ◽  
Protein Biosynthesis ◽  
Amino Acid Incorporation ◽  
Acid Incorporation ◽  
Polyuridylic Acid ◽  
Liver Ribosomes

1. The liver ribosomes of rats given cycloheximide by intraperitoneal injection incorporate less amino acid into protein than ribosomes from control rat liver when they are incubated in vitro with excess of Sephadex-treated cell sap. The effect is rapid, marked and persistent. 2. Cell sap from liver of cycloheximide-treated animals is inhibitory but the inhibition can be relieved almost entirely by treating the cell sap with Sephadex. No damage has been done to the cell-sap factors: it is suggested that the dissolved cycloheximide in the cell sap causes the inhibition. 3. Cycloheximide added in vitro inhibits amino acid incorporation into protein in the presence or absence of polyuridylic acid. The inhibition is lessened by addition of excess of cell sap but is not abolished. 4. The differences between these results and those obtained with mouse liver (Trakatellis, Montjar & Axelrod, 1965) might arise because of species differences in sensitivity to the drug.

Protein synthesis by free and bound rat liver ribosomes in vivo and in vitro

1963 ◽  
Vol 7 (2) ◽  
pp. 122-129 ◽  
Author(s):  
Edgar C. Henshaw ◽  
Tadeusz B. Bojarski ◽  
Howard H. Hiatt
Keyword(s):  
Protein Synthesis ◽  
Rat Liver ◽  
Liver Ribosomes

Analysis of the Mechanism of Microtubule Dynamic Instability Using a UV Microbeam to Sever Elongating Microtubules

1988 ◽  
Vol 46 ◽  
pp. 122-123
Author(s):  
R.A Walker ◽  
S. Inoue ◽  
E.D. Salmon
Keyword(s):  
Dynamic Instability ◽  
Microtubule Dynamic ◽  
Gtp Hydrolysis ◽  
Abrupt Transition ◽  
Microtubule Associated Proteins ◽  
Asymmetrical Structure ◽  
Associated Proteins

Microtubules polymerized in vitro from tubulin purified free of microtubule-associated proteins exhibit dynamic instability (1,2,3). Free microtubule ends exist in persistent phases of elongation or rapid shortening with infrequent, but, abrupt transitions between these phases. The abrupt transition from elongation to rapid shortening is termed catastrophe and the abrupt transition from rapid shortening to elongation is termed rescue. A microtubule is an asymmetrical structure. The plus end grows faster than the minus end. The frequency of catastrophe of the plus end is somewhat greater than the minus end, while the frequency of rescue of the plus end in much lower than for the minus end (4).The mechanism of catastrophe is controversial, but for both the plus and minus microtubule ends, catastrophe is thought to be dependent on GTP hydrolysis. Microtubule elongation occurs by the association of tubulin-GTP subunits to the growing end. Sometime after incorporation into an elongating microtubule end, the GTP is hydrolyzed to GDP, yielding a core of tubulin-GDP capped by tubulin-GTP (“GTP-cap”).

Sign in / Sign up

Export Citation Format

Share Document