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Results for “Protein Biosynthesis”

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At least 37 records · Page 2Linked to original sources
PubMed1976

Inhibition by 5-thio-D-glucopyranose of protein biosynthesis in vitro in spermatids from rat testis.

The effect of 5-thio-D-glucopyranose (thioglucose) upon protein biosynthesis in vitro was examine in testes from mature rats. Thioglucose in vitro is without demonstrable effect upon incorporation of L-[U-14C]phenylalanine into protein by whole testis but inhibits this incorporation by a purified fraction of immature spermatids (stages 1--8) prepared by centrifugal eluctriation; the inhibition is observed with or without glucose added in vitro and is concentration dependent in the range 1--50 mM. Similar inhibition is observed with three other 14C-labeled amino acids (leucine, lysine and glutamate). Mature spermatids (greater than stage 8) and other heterogenous fractions of testicular cells prepared by the same method also show inhibition by thioglucose of incorporation of phenylalanine into protein so that it is not possible to say that the effect is confined to spermatids although it is most pronounced in these cells. Inhibition of protein synthesis in vitro is also observed when thioglucose was administered in vivo (33 mg/kg body wt./day). This change occurs at the minimal dose observed by other workers to produce arrest of spermatogenesis and hence infertility.

Animals↗
PubMed1975

Protein biosynthesis by the pulmonary alveolar macrophage. Comparison of synthetic activity of suspended cells and cells on surfaces.

An effort to optimize conditions for studying protein biosynthesis by the pulmonary alveolar macrophage in vitro has led to a comparative analysis of the activity of suspended and adherent cells. A number of differences were observed. (1) Suspended cells synthesized protein for only a limited period of time, after which they responded only partially to incubation in fresh medium. This was true even under reincubation conditions in which the cells were allowed to adhere to a surface. Adherent cells, however, synthesized protein during a longer period of time and were fully capable of responding to new medium within the time periods examined. (2) Analyses of the radioactive proteins synthesized using a dual-isotope technique suggested that, during a period of 2 hours, suspended cells synthesized relatively smaller quantities of high molecular weight proteins than adherent cells. (3) The administration of a phagocytic load (zymosan; particle to cell ratio, 10:1) inhibited by 20 per cent the incorporation of isotopic amino acid into protein during a period of 3 hours. The same phagocytic load, however, stimulated incorporation by 20 per cent in adherent cells. (4) The rate of particle uptake measured using oil red O-albumin complexes decreased by approximately 50 per cent in suspended cells preincubated for 2 hours, but was maintained in similarly preincubated adherent cells. It was concluded that pulmonary alveolar macrophages incubated adhered to a surface are more appropriate for metabolic studies than are pulmonary alveolar macrophages incubated in suspension.

Animals↗
PubMedDate not supplied

On the origin of protein biosynthesis.

There is a very close steric relationship between the codon-anticodon site which accounts for the genetic code dictionary and a polynucleotide replicase site. Protein biosynthesis must therefore have arisen out of a primaeval polynucleotide replicase system.

Anticodon↗
PubMed1975

[Diabetes mellitus and control of protein biosynthesis in rat liver (author's transl)].

Protein synthesis of liver risobosmes is markedly reduced in diabetes mellitus. This finding is well correlated with the protein catabolic state of insulin deficiency in general and with the reduction of protein synthesis by muscle ribosomes in particular. However, with regard to the mechanism of the amino acid incorporation by muscle ribosomes there is indication for an additional participation of transcription in the diabetes-induced reduction of protein synthesis by liver ribosomes. There is support for the hypothesis of an additional effect of diabetes on ribosomal wash proteins and on synthesis of ribosomal ribonucleic acids with consecutive reduction of conformation of ribosomal subunits or binding of ribosomal subunits to template RNA respectively.

Animals↗
PubMedDate not supplied

[Alkane-induced protein biosynthesis in Pseudomonas aeruginosa].

Protein disc-electrophoregrams of cell-free homogenates have been compared in the "non-adapted" and "preliminarily-adapted" to n-hexane strains of Pseudomonas aeruginosa. A statistically reliable increase in the content of protein by 60 per cent was found in fractions a (M. W. 70,000) and b (M. W. 130,000) when the cells of both strains were gorwn on hexane as compared to the cells cultivated on glucose. The content of protein in each a and b band was about 4 per cent of the total cell protein before the induction by hexane. No differences were found when the cells of the two strains were grown on identical substrates. The induced proteins are supposed to belong to the system of primary oxidation of n-alkanes with short chains and to be localized in the cytoplasm of Ps. aeruginosa.

Alkanes↗
PubMedDate not supplied

[Ultrastructural and functional expression of the hepatocyte genome in conditions of prolonged inhibition of protein biosynthesis with cycloheximide. II].

The correlation of changes in sedimentary properties of polysome preparation and ultrastructure of the rough endoplasmatic reticulum in the rat liver cells was found in dynamics of the protein biosynthesis inhibition by cycloheximide (CH1). In particular, 6 hrs after CHI introduction the greatest fragmentation of the reticulum is accompanied by the greatest destruction of polysomes; however at the end of the 24-hour period a tendency is observed to restore the studied components of the protein synthesis system.

Amino Acids↗
PubMed1979

[Protein biosynthesis in the rat liver in natural fluctuations of the steroid background].

The results of the study of protein and RNA biosynthesis and inducation of glucose-6-phosphatase activity in the rat liver at natural (seasonal) fluctuations of the steroid background are presented. It is shown that the adrenal gland seasonal activation increases incorporation of precursors labeled (l14C-leucine and l14C-orotic acid) into total liver proteins and RNA and enhances glucose-6-phosphatase activity in the rat liver. The conclusion is drawn that the changes in the endogenous corticosteroid level have regulative significance for protein biosynthesis in the rat liver.

Adrenal Cortex Hormones↗
PubMed1979

Pulvomycin, an inhibitor of prokaryotic protein biosynthesis.

Antibiotic 1063-Z isolated from culture fluids of Streptoverticillium mobaraense was identified as pulvomycin. Pulvomycin was observed to inhibit protein biosynthesis in growing cells of Bacillus brevis. The poly(U)-directed poly(Phe) synthesis in cell-free systems of Bacillus brevis and Escherichia coli was highly susceptible to the antibiotic. Pulvomycin did not affect the transfer of Phe to tRNA. The results suggest that the target of pulvomycin action is the polypeptide chain elongation.

Anti-Bacterial Agents↗
PubMed1978

Participation of X47-fluorescamine modified E. coli tRNAs in in vitro protein biosynthesis.

The reaction of fluorescamine with primary amino groups of tRNAs was investigated. The reagent was attached under mild conditions to the 3'-end of tRNAPhe-C-C-A(3'NH) from yeast and to the minor nucleoside x in E. coli tRNAArg, tRNALys, tRNAMet, tRNAIle and tRNAPhe. The primary aliphatic amino groups of these tRNAs react specifically so that the fluorescamine dye is not attached to the amino groups of the nucleobases. E. coli tRNA species modified on the minor nucleoside X47 can all be aminoacylated. An involvement of the minor modified nucleoside X47 in the tRNA: synthetase interaction is detected. Native tRNALys-C-C-A from E. coli can be phenylalanylated by phenylalanyl-tRNA synthetase from yeast, whereas this is not the case for fluorescamine treated tRNALys-C-C-A(XF47). Pre-tRNAPhe-C-C-A(XF47) forms a ternary complex with the elongation factor Tu:GTP from E. coli, binds enzymatically to the ribosomal A-site and is active in poly U dependent poly Phe synthesis. Fluorescamine-labelled E. coli tRNAs provide new substrates for the study of protein biosynthesis by spectroscopic methods.

Bacterial Proteins↗
PubMedDate not supplied

[Effect of long-term space flight on protein biosynthesis in different rat tissues and organs].

Protein synthesis in the heart, lungs, liver, pancreas, thymus, kidneys, skeletal muscles and testes of the 22-day Cosmos-605 flight and synchronous rats was studied with the aif of 14C-amino acid incorporation. On the 2nd postflight day both flight and synchronous rats showed an increased synthesis of heart sarcoplasmatic proteins. On the 26th postflight day the rate of incorporation was normal. On the 2nd and 26th days the synthesis of myofibrillar proteins in the m. quadriceps femoris was inhibited in flight animals postflight day the rate of incorporation was normal. On the 2nd and 26th days the syn-only. On the 2nd and 26th days the liver of the flight and synchronous rats showed qualitatively similar changes in protein metabolism of subcellular structures. No changes in the protein synthesis of other organs tested were detected.

Animals↗
PubMed1979

[Effect of silicoorganic compounds on protein biosynthesis in granulation-fibrous tissue].

The authors studied the effect of propoxysilatran (POS) on the biosynthesis of the main connective tissue biopolymeres. The use of POS in the form of 0.5 and 2.0% ointments on lanolin-vaseline base caused stimulation of cellular proliferation in the granulation fibrous tissue developing in the open skin defects of albino rats. Stimulation of cellular proliferation in these animals was accompanied by increase of collagen biosynthesis and of noncollagen proteins. In concentrations of 10(-3)--10(-4) M POS caused intensification of collagen biosynthesis (formation of peptide-bound nondialyzed 14C-oxyproline) in vitro in the cartilage tissue of chick embryos. Thus, silatrans are biologically-active substances producing a regulating effect on the course of the reparative-proliferative processes in the connective tissue.

Animals↗
PubMed1975

Studies on the biochemical action of ginseng saponin. I. Purification from ginseng extract of the active component stimulating serum protein biosynthesis.

Systematic isolation and purification of the biologically active component of ginseng extract were followed by observing the incorporation of labeled leucine into serum protein at 6 hr after a single intraperitoneal injection in a mouse. Ginseng saponin mixture (fraction 5) exhibited high activity for such incorporation. Seven saponins were isolated from fraction 5 by means of preparative TLC, and assayed. Administration of all these saponins (ginsenoside-Rb2, Rc, Rc2, Rd, Re, and Rg1)except for ginsenoside-Rb1, caused an increase of leucine incorporation over that in control animals. The incorporation rate was directly proportional to the dose in the case of ginsenoside-Rd, which had the highest activity. The increase specific radio-activity of serum protein was not due to a decrease in the pool size of free amino acids in the liver. It was conclusively shown that the active component stimulating serum protein biosynthesis is saponin.

Animals↗
PubMed1977

Properties of phenylalanine transfer ribonucleic acid with modified 3'-terminal end in protein biosynthesis using a rabbit reticulocyte cell-free system: effect of the replacement of cytidine residues from the CpCpA end of tRNA by 5-iodocytidine or 2-thiocytidine.

Phe-tRNA Phe from yeast containing 2-thiocytidine or 5-iodocytidine in position 75 of the polynucleotide chain or Phe-tRNA Phe in which both positions 74 and 75 were substituted by 5-iodocytidine were investigated in the poly U-dependent polyphenylalanine synthesis on ribosomes from rabbit reticulocytes. Phe-tRNA Phe-Cps2CpA was nearly as active as the native Phe-tRNA Phe-CpCpA in the overall process. Phe-tRNA Phe-Cpi 5CpA as well as Phe-tRNA Phe-i5Cpi 5CpA were considerably less active than the native species. Investigation of individual steps of protein biosynthesis with these modified substrates revealed that the donor activity of peptidyl-tRNAs which contain 5-iodocytidine in their 3'-terminus is strongly imparied suggesting exacting structural requirements for the interaction of the CpCpA end of tRNA with the ribosomal P-site.

Animals↗
PubMedDate not supplied

[Protein biosynthesis of the xenogeneic heart during perfusion with the aid of a donor].

Biosynthesis of sarcoplasmic and contractile proteins was studied in cat heart, extracorporeally connected to the rabbit circulation. Biosynthesis of sarcoplasmic proteins was inhibited by 34-40% in ventriculus dexter of the perfused xenogenic heart. Heteroperfusion caused an increased incorporation of 35S-methionine into total proteins of the right auricle and of the interventricular septa and also into contractile proteins of both myocardium ventricles of rabbit-donor. The heteroperfusion did not affect the penetration of the labelled amino acid into various parts of perfused and donor hearts.

Animals↗
PubMed1976

[On the influence of oral antidiabetics on protein biosynthesis in vitro (author's transl)].

Inhibition of protein synthesis is one of the few side effects of sulfonylureas and biguanides. Regarding our results obtained with hepatic polyribosomes from diabetic and from control animals, with ribosomes directed by polyuridylic acid as a synthetic messenger, and by centrifugation of the ribosomes through sucrose gradients there is evidence of a direct inhibiting effect of tolbutamide on liver ribosomes. The effect of butyl-biguanide depends on the system used for in vitro protein synthesis. While it is inhibiting protein synthesis of normal liver ribosomes regardless of the attached messenger, it stimulates the incorporation of amino acids by ribosomes from diabetic rats directed by endogenous or by synthetic messengers. The specific pattern of ribosomal distribution in sucrose gradients is unchanged by the administration of tolbutamide to the animal prior to its decapitation. However, butyl-biguanide leads to reduction of the polyribosomal portion of liver ribosomes from normal animals while it is without any furhter effect on the amount of polyribosomes already reduced in diabetes mellitus.

Animals↗
PubMed1979

Studies on the function of two adjacent N6,N6-dimethyladenosines near the 3' end of 16 S ribosomal RNA of Escherichia coli. II. The effect of the absence of the methyl groups on initiation of protein biosynthesis.

The effect of the presence or absence of methyl groups on the N6 atoms of two adjacent adenosines near the 3' end of 16 S rTNA of Escherichia coli on initiation of protein biosynthesis has been studied using wild type (methylated) and kasugamycin-resistant (unmethylated) E. coli ribosomes (see preceding paper (Poldermans, B., Goosen, N., and Van Knippenberg, P. H. (1979) J. Biol. Chem. 254, 9085--9089)). Conditions of pH, temperature, and ionic strength at which binding of fMet-tRNA to ribosomes proceeds maximally are the same for wild type and mutant ribosomes. Mg2+- and factor-dependent dissociation of ribosomes as well as the association of the subunits is also the same for methylated and unmethylated ribosomes. Binding of fMet-tRNA to wild type and to mutant 70 S ribosomes requires the same amount of the three initiation factors. However, optimal fMet-tRNA binding to unmethylated 30 S ribosomes needs more of initiation factor 3 than does binding to methylated 30 S ribosomes, provided that initiation factor 1 is absent. This difference is completely abolished when mutant 30 S ribosomes are methylated using purified methylase from the wild type strain and the methyl donor S-adenosylmethionine.

Adenosine↗