Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rat liver contains a high concentration (7-8mM) of reduced glutathione and its level changes rapidly when starving or feeding rats. We concluded that one of the functions of liver glutathione was to act as a reservoir of cysteine. When starved rats were fed a protein-free diet, the increase in liver glutathione was dependent on the amount of cysteine added to the diet. A cysteine-dependent increase of glutathione was also observed in rats fed a diet containing gelatin with cysteine, but the increase was relatively lowered compared with rats fed a protein-free diet containing the same amount of cysteine. This suppression of the increase in glutathione was observed much more clearly when the gelatin diet was fortified with tryptophan in addition to cysteine. In the presence of tryptophan, L-[35S]-cysteine in the diet appeared to be incorporated primarily into liver and serum proteins, and degradation of liver glutathione must also have been enhanced. Addition of excess cysteine to the diet masked the effects of gelatin and tryptophan, stimulated glutathione synthesis in the liver as well as incorporation of dietary cysteine into protein fractions. Prolonged starvation of rats or injection of dibutyryl-3',5'-cyclic AMP lowered the glutathione level,but the level did not decrease below 2 to 3 mM. These findings suggest that there may be at least two pools of glutathione. A labile fraction, constituting one-third to one-half the total liver glutathione, probably serves as a reservoir of cysteine which can be released by gamma-glutamyl-transferase when necessary.
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PMID:Rat liver glutathione: possible role as a reservoir of cysteine. 1 67

A purification and some properties of proteinase A from yeast are described. A specific macromolecular inhibitor of proteinase A from yeast cytosol has been isolated and shown to be a protein (molecular weight 7,700) consisting of a majority of polar amino acids. Proline, arginine, cysteine and tryptophan were not detected in the inhibitor. Possible biological functions of proteinase A and the proteinase A-inhibitor (and of other yeast proteinases and their inhibitors) in the following processes are discussed: general protein turnover, catabolite inactivation of enzymes, enzyme degradation at starvation and at transition to spore formation, and activation of pre-enzymes and precursor proteins by limited proteolysis.
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PMID:Characteristics and functions of proteinase A and its inhibitors in yeast. 2 96

When treated with chloramphenicol, Escherichia coli 15T minus produces two new species (IV and V) of transfer ribonucleic acid specific for phenylalanine in addition to the major normal species (II) and two minor normal species (I and III), which are seen as distinct components upon fractionation by chromatography on columns of benzoylated diethylaminoethyl-cellulose. Species IV is produced when cells are grown in iron-deficient medium and is, therefore, probably deficient in the 2-methylthio modification of N-6-(delta-2-isopentenyl) adenosine. A new minor species (Va) also appears under those conditions. All of the new components elute earlier than the major normal species. Addition of chloramphenicol to iron-deficient cells leads to the production of species V, and that production is blocked by rifampin, as is the production of species IV. Thus, species IV and V appear to be transcriptional products. Although E. coli 15T minus appears to be rel plus, starvation for methionine or cysteine leads to the accumulation of species IV (without addition of chloramphenicol); rifampin blocks the accumulation. Species V is still produced on addition of chloramphenicol to starved cultures. Starvation for arginine or tryptophan does not alter the chromatographic profile from the normal case. Treatment with permanganate indicates that species II and IV contain isopentenyladenosine but that species V does not. Species V appears to be deficient in both isopentenyl and methylthio modifications of adenosine and perhaps at least one other modification, because removing the isopentenyl moiety from adenosine does not convert species IV into species V, but converts it into species Va. A precursor relationship among species V, VI, and II is suggested by following the chromatographic profile of phenylalanine transfer ribonucleic acid during recovery of E. coli from treatment with chloramphenicol; the various species increase and decrease in a sequential manner.
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PMID:Precursor relationship of phenylalanine transfer ribonucleic acid from Escherichia coli treated with chloramphenicol or starved for iron, methionine, or cysteine. 4 64

Flagellin, the protomeric subunit of bacterial flagella, contains no cysteine. We have detected the incorporation of trace quantities of 35S-cysteine into flagellin, highly purified and then resolved by SDS polyacrylamide gel electrophoresis, to measure mistranslation in vivo. Under normal conditions, this value is about 6 X 10(-4) pmoles cysteine per pmole flagellin. This value is greatly increased during growth in low concentrations of streptomycin and neomycin, antibiotics which are known to stimulate misreading in vitro. Of the specific types of misreading which streptomycin stimulates in vitro, only misreading of the CGU and CGC arginine codons could give rise to illegitimate incorporation of cysteine. In agreement, partial arginine starvation increases the incorporation of 35S-cysteine into flagellin in a relA- mutant, with or without streptomycin, but has no such effect in its isogenic relA+ partner- Assuming from these results that 35S-cysteine incorporation into flagellin reflects misreading of CGU/C coda, we deduce a misreading probability per codon in the range of 10(-4).
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PMID:Mistranslation in E. coli. 13 85

Molybdate and selenate are structural analogs of sulfate that inhibit synthesis of adenosine 5'-phosphosulfate by ATP sulfurylase (sulfate adenylyltransferase, ATP:sulfate adenylyltransferase, EC 2.7.7.4) in crude extracts of tobacco XD cells. Both of these anions derepress ATP sulfurylase in cells growing on sulfate, but not in cells growing on L-cysteine. However, the two anions appear to derepress by different mechanisms. Molybdate caused derepression only at concentrations that were in excess over sulfate and were sufficient to inhibit growth and protein accumulation, indicating that the derepression resulted from sulfur starvation. Selenate caused derepression at one-tenth the concentration of sulfate, a concentration of selenate that was subtoxic, while toxic levels of selenate produced far less derepression. The susceptibility of the tobacco cells to selenate toxicity was high under conditions of sulfur nutrition that derepress ATP sulfurylase, and low under conditions that repress ATP sulfurylase, in agreement with the idea that selenate acts via a functional sulfate assimilation pathway. Since it is known that selenate is incorporated into analogs of sulfur compounds, it is proposed that the tobacco cells synthesize the seleno-analog of the end product of the sulfate pathway responsible for repression, and the seleno-analog antagonizes the normal end product in the repression mechanism, the net result being derepression of ATP sulfurylase by selenate.
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PMID:Derepression of ATP sulfurylase by the sulfate analogs molybdate and selenate in cultured tobacco cells. 26 28

The stability of tryptophan biosynthetic enzyme activities was examined in cultures of repressor-negative (trpR) strains of Escherichia coli K-12 incubated under conditions of nutrient starvation of chloramphenicol inhibition. The results show that four of the five activities examined are stable under most nongrowing conditions, whereas one activity, indoleglycerol phosphate (InGP) synthetase, carried by the trpC protein, is unstable under most conditions tested. Phosphoribosylanthranilate (PRA) isomerase activity, which is also carried by the trpC protein, is unstable during starvation for ammonium, cysteine, or sulfate but is stable under other nongrowing conditions where InGP synthetase is not. InGP synthetase activity but not PRA isomerase activity is also diminished about twofold in cultures using glycerol as a carbon-energy source. These results indicate that one or both activities of the trpC protein is specifically inactivated under several culture conditions. Experiments with antibodies to the trpC protein show that sulfate-starved and ammonium-starved cultures contain 20 to 40% less immunologically reactive trpC protein than unstarved cultures. This indicates that the trpC protein is probably partially degraded under these conditions. During recovery from sulfate starvation or ammonium starvation, cultures slowly regain normal levels of InGP synthetase and PRA isomerase activities, suggesting that inactivation may be reversible.
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PMID:Inactivation and partial degradation of phosphoribosylanthranilate isomerase-indoleglycerol phosphate synthetase in nongrowing cultures of Escherichia coli. 32 57

Constant levels of amino acids enhanced the velocity of Bacillus subtilis 60015 cells about 2-fold and stimulated the response in motility assays. The stimulation of velocity did not occur via the receptors for chemotaxis. Cysteine and methionine, general inhibitors of chemotaxis, both completely inhibited the smooth response in a temporal gradient of attractant. After methionine starvation B. subtilis 60015 showed no measurable response in a temporal gradient of attractant, this in contrast to the effect observed with some other bacteria. Addition of methionine to starved cells restored the response toward attractant. Revertants of B. subtilis 60015 for methionine requirement could not be starved and showed a normal behavior toward temporal gradients of attractant.
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PMID:The effect of amino acids on the motile behavior of Bacillus subtilis. 40 81

When guinea-pig lymph node cells were exposed to ConA in a culture medium lacking glutamine or cysteine, no DNA synthesis occurred. The addition of the missing acid to ConA-treated lymphocytes submitted to glutamine or cysteine starvation for 40 h allowed the synthesis of DNA to take place after a period of only 10-12 h. The synthesis of DNA is preceded by a rapid increase of 3H-uridine incorporation into RNA and of 3H-leucine incorporation into protein which occurred a few hours after addition of the missing amino acid. When cycloheximide was added to lymphocytes exposed to ConA in a glutamine or cysteine deprived medium, a relative enhancement of uridine incorporation was observed. No such effect was provoked by puromycin. These results suggest the possibility of a control system in lymphocytes similar to those described in microbial cells for amino acid control of RNA synthesis.
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PMID:Influence on certain amino acids on steps leading to DNA synthesis in concanavalin A-treated guinea-pig lymphocytes. 59 38

A glycerol-requiring mutant of Salmonella typhimurium was used in a study of the biosynthesis and assembly of a structural lipoprotein in the cell envelope of gram-negative bacteria. Upon removal of glycerol from the growth medium, the biosynthesis of lipoprotein, as measured by radioactive arginine incorporation, was reduced by the same extent as that of other envelope proteins, the cumulative incorporation of arginine being 20% of that of the unstarved control cells. However, the incorporation of radioactive palmitate into lipoprotein was more severely curtailed after glycerol starvation, the cumulative rate of which was 8% of that observed in the unstarved cells. It was further observed that the lipoprotein synthesized in the glycerol-starved cells was more enriched in unmodified cysteine, which is known to be the N-terminal amino acid of lipoprotein, than that synthesized in the unstarved cells. We conclude that the synthesis of the apoprotein portion of Braun's lipoprotein proceeds independently of the attachment of diglyceride to the sulfhydryl group of the N-terminal cysteine and may, in fact, precede the incorporation of the diglyceride moiety.
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PMID:Biosynthesis and assembly of envelope lipoprotein in a glycerol-requiring mutant of Salmonella typhimurium. 76 31

Sulfur-deficient tRNA, isolated from Escherichia coli HfrC, rel-, met-, cys-, lambda, after cysteine starvation, was found to have an increased acceptance of isoleucine in proportion to the deficiency of 4-thiouridine. Isoleucine acceptance was not altered in the presence of other amino acids of CTP, and the higher acceptance was observed over a wide range of magnesium, isoleucine, tRNA and enzyme concentrations. The Vmax value for sulfur-deficient tRNA was more than three times greater than observed for normal tRNA. Methylated albumin kieselguhr (MAK) chromatography revealed three isoacceptor peak for normal tRNA, while sulfur-deficient tRNA was missing tRNAile, and exhibited a larger, shifted peaks for tRNA normal tRNA, while sulfur-deficient tRNA was missing tRNAille 2, and exhibited a large shifted peak for tRNAile 3 . Treatment with crude RNA sulfurtransferase both lowered the isoleucine acceptance for sulfur-deficient tRNA to that seen for normal tRNA, and restored the missing isoacceptor on MAK. The possibility that thionucleotides may play a role in the aminoacylation of tRNAile in E. coli is discussed.
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PMID:Increased isoleucine acceptance by sulfur-deficient transfer RNA from Escherichia coli. 78 31


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