Stoffwechselregulation durch den Zellwandbaustein Kieselsäure: Polgrößenänderungen von a-Ketoglutarsäure, Aminosäuren und Nucleosidphosphaten

1968 ◽  
Vol 23 (2) ◽  
pp. 268-271 ◽  
Author(s):  
D. Werner
Keyword(s):  
Glutamic Acid ◽  
Aspartic Acid ◽  
Rna Synthesis ◽  
Acid Synthesis ◽  
Centric Diatom ◽  
Free Medium ◽  
Acetyl Coa ◽  
E Coli ◽  
Acid Pool ◽  
Acetyl Coa Pathway

When the centric diatom Cyclotella cryptica is grown in a Si (OH) 4-free medium, the glutamic acid pool decreases within 3 hours to a third of the original value, whereas the aspartic acid pool is reduced by only about 20 per cent. The pools of nucleosid-triphosphates and of glycerol-1-phosphate remain unaffected during this time. The nucleosid-diphosphates pool decreases in the same way as that of aspartic acid. The decrease in the glutamic acid pool precedes the inhibition of total protein synthesis in Si (OH) 4-deficient cells, and a significant decrease in the a-ketoglutarate pool precedes the decrease of the glutamic acid content. Already within 60 minutes ofter incubation in a Si (OH) 4-free medium, the content of a-ketoglutarate is decreased to one third of the normal value. On the other hand, the acetyl CoA pathway (enhanced fatty acid synthesis) is not inhibited. The results suggest, that the Si (OH) 4-metabolism interferes with reactions between the condensing enzyme (acetyl-CoA and oxalacetate) and a-ketoglutarate. The delay between inhibition of protein- and RNA-synthesis and the different changes in the pools of amino acids and nucleosid-triphosphates resemble the regulation of the nucleosid-triphosphate pool and RNA-synthesis in amino acid starved strains of E. coli (EDLIN and NEUHARD) 1, though the primary causes are quite different.

Some enzymic syntheses of 15N-L-aspartic acid and 15N-L-glutamic acid

1969 ◽  
Vol 47 (3) ◽  
pp. 411-415 ◽  
Author(s):  
J. A. Zintel ◽  
A. J. Williams ◽  
R. S. Stuart
Keyword(s):  
Glutamic Acid ◽  
Aspartic Acid ◽  
Fumaric Acid ◽  
Aspartate Aminotransferase ◽  
Efficient Utilization ◽  
E Coli ◽  
Acid Dehydrogenase ◽  
Acid Catalyzed ◽  
Catalyzed Reactions ◽  
Enzyme Catalyzed Reactions

Some methods for the preparation of 15N-L-aspartic acid and 15N-L-glutamic acid using enzyme catalyzed reactions are described. 15N-L-Aspartic acid is prepared by the addition of ammonia to fumaric acid, catalyzing the reaction with aspartase which was partially purified from E. coli. 15N-L-Glutamic acid with a high 15N/14N ratio is prepared by transamination with 15N-L-aspartic acid catalyzed by aspartate aminotransferase. 15N-L-Glutamic acid with a low 15N/14N ratio is prepared by a glutamic acid dehydrogenase catalyzed exchange of L-glutamic acid with 15N-ammonia. These enzymes are commercially available. Since efficient utilization of 15N is obtained, aspartic acid or glutamic acid may be prepared with any desired 15N/14N ratio.

Modeling the Negative Feedback Mechanism in the Enzyme Carboxyltransferase

2011 ◽  
Author(s):  
Xiaoyu Cai ◽  
Marcio de Queiroz ◽  
Glen Meades ◽  
Grover Waldrop
Keyword(s):  
Fatty Acid ◽  
Negative Feedback ◽  
Acid Synthesis ◽  
Feedback Mechanism ◽  
Mass Action ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Mass Action Kinetics ◽  
E Coli ◽  
Negative Feedback Mechanism

The enzyme acetyl-CoA carboxylase catalyzes the first committed step in fatty acid synthesis in all organisms. The E. coli form of the carboxyltransferase subunit was recently found to regulate its own activity and expression by binding its own mRNA. By binding acetyl-CoA or the mRNA encoding its own subunits, Carboxyltransferase is able to sense the metabolic state of the cell and attenuate its own translation and enzymatic activity using a negative feedback mechanism. In this paper, this network of interactions is modeled mathematically using mass action kinetics. Numerical simulations of the model show agreement with experimental results.

ABSENCE OF DIFFERENTIAL RNA SYNTHESIS BY THE X CHROMOSOMES OF COW LEUCOCYTES

1970 ◽  
Vol 12 (1) ◽  
pp. 44-51 ◽  
Author(s):  
K. Mann ◽  
B. B. Mukherjee
Keyword(s):  
X Chromosome ◽  
Ribonucleic Acid ◽  
Rna Synthesis ◽  
Acid Synthesis ◽  
Free Medium ◽  
X Chromosomes ◽  
Inactive X Chromosome

The patterns of ribonucleic acid synthesis by the two X chromosomes during mitotic interphase were studied at metaphase. Cultured cow leucocytes were pulsed with H3-uridine for 15 minutes, washed, resuspended in tracer-free medium and collected at different times after the end of the pulse. Autoradiography of the cells failed to show any significant differences in the number of grains located over the two X chromosomes. The incorporation of H3-uridine into RNA by both X chromosomes indicates that at least part of the 'inactive' X chromosome must be actively synthesizing some RNA.

The metabolism of 14C-urea by white spruce seedlings in light and darkness

1973 ◽  
Vol 51 (6) ◽  
pp. 1197-1211 ◽  
Author(s):  
D. J. Durzan
Keyword(s):  
Carbon Dioxide ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Urease Activity ◽  
De Novo ◽  
White Spruce ◽  
Acid Synthesis ◽  
Transfer Rna ◽  
Ammonium Ions ◽  
Specific Activities

Weak urease activity was detected in 2-week-old white spruce seedlings. The addition of urea to these seedlings increased urease activity in light compared to darkness. Urease was localized in the cytoplasm mainly in the epidermal cells, and to a lesser extent in vascular tissues and at the shoot apex.In light, the early products of 14C-urea indicated the release of 14C-carbon dioxide and ammonium ions. Radioactivity appeared in the anionic and neutral fractions and then in alanine, serine, and glycine, just as in the fixation of 14C-bicarbonate. By 4 h most radioactivity resided in glutamic acid and alanine. This pattern was associated with increased protein synthesis, and with high levels of free glutamine. Serine, glycine, alanine, and carbamyl aspartic acid had high specific activities.In darkness, radioactivity in alanine persisted, but levels in serine, glycine, and protein were low. Most radioactivity eventually resided in asparagine. Radioactive urea and citrulline were kept at higher levels than in light. Glutamic acid, citrulline, and carbamyl aspartic acid had the greatest specific activities. In light and darkness, carbamyl derivatives were formed more readily from 14C-urea than from 14C-bicarbonate.Carbamyl phosphate was implicated as a precursor of citrulline and arginine as well as for carbamyl aspartic acid. In light, radioactivity was recovered from ribosomal (25, 23, 18, 16, and 5 S) and transfer RNA (4 S). This resided mainly in uracil and cytosine. By contrast, in DNA, radioactivity was recovered mainly from thymine, cytosine, and 5-methylcytosine. In rapidly growing seedlings, urea contributed to de novo nucleic acid synthesis mainly through pyrimidine pathways via carbamyl aspartic acid.

scholarly journals Dietary glutamic acid and aspartic acid as biomarkers for predicting diabetic retinopathy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
So Young Park ◽  
Jieun Kim ◽  
Jung Il Son ◽  
Sang Youl Rhee ◽  
Do-Yeon Kim ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Education Level ◽  
Screening Rate ◽  
Food Records ◽  
Acid Intake ◽  
Lower Education Level ◽  
Lower Education

AbstractThe screening rate of diabetic retinopathy (DR) is low despite the importance of early diagnosis. We investigated the predictive value of dietary glutamic acid and aspartic acid for diagnosis of DR using the Korea National Diabetes Program cohort study. The 2067 patients with type 2 diabetes without DR were included. The baseline intakes of energy, glutamic acid and aspartic acid were assessed using a 3-day food records. The risk of DR incidence based on intake of glutamic acid and aspartic acid was analyzed. The DR group was older, and had higher HbA1c, longer DM duration, lower education level and income than non-DR group (all p < 0.05). The intake of total energy, glutamic acid and aspartic acid were lower in DR group than non-DR group (p = 0.010, p = 0.025 and p = 0.042, respectively). There was no difference in the risk of developing DR according to the intake of glutamic acid and ascorbic acid. But, aspartic acid intake had a negative correlation with PDR. Hence, the intake of glutamic acid and aspartic acid did not affect in DR incidence. However, lower aspartic acid intake affected the PDR incidence.

scholarly journals INHIBITING EFFECT OF THE NEW CYTOTOXIC ANTIBIOTIC DAUNOMYCIN ON NUCLEIC ACIDS AND MITOTIC ACTIVITY OF HELA CELLS

1965 ◽  
Vol 27 (3) ◽  
pp. 545-550 ◽  
Author(s):  
A. Di Marco ◽  
R. Silvestrini ◽  
S. Di Marco ◽  
T. Dasdia
Keyword(s):  
Mitotic Activity ◽  
Rna Synthesis ◽  
Thymidine Incorporation ◽  
Acid Synthesis ◽  
Acetyl Derivative ◽  
Total Inhibition ◽  
Nuclear Rna ◽  
Nucleolar Rna ◽  
Higher Doses

The effect has been studied of Actinomycin D, Daunomycin (Da.), and Da. N acetyl derivative on mitotic activity and on the nucleic acid synthesis of in vitro HeLa cell cultures. The experiments were carried out by means of the radioautographic technique using stripping films. The relative uptake of thymidine-H3 and uridine-H3 was determined by means of the reduced silver grain count present in the nuclei of controls and treated cells. The mitotic activity and thymidine incorporation were noticeably reduced by Daunomycin and Actinomycin, whereas both processes appeared less affected by Da. N acetyl derivative. As regards nuclear RNA synthesis, all three antibiotics at low doses chiefly inhibit nucleolar RNA synthesis. On the other hand, whilst Actinomycin at higher doses causes an almost total inhibition of the synthesis of the whole nuclear RNA, in Daunomycin- and Da. N acetyl derivative-treated cells extranucleolar RNA synthesis is less susceptible to inhibition.

Biodegradation of copoly(L-aspartic acid/L-glutamic acid) in vitro

Biopolymers ◽  
1990 ◽  
Vol 29 (3) ◽  
pp. 549-557 ◽  
Author(s):  
Toshio Hayashi ◽  
Makoto Iwatsuki
Keyword(s):  
Glutamic Acid ◽  
Aspartic Acid

scholarly journals HFA1 Encoding an Organelle-specific Acetyl-CoA Carboxylase Controls Mitochondrial Fatty Acid Synthesis inSaccharomyces cerevisiae

2004 ◽  
Vol 279 (21) ◽  
pp. 21779-21786 ◽  
Author(s):  
Ursula Hoja ◽  
Sandra Marthol ◽  
Jörg Hofmann ◽  
Sabine Stegner ◽  
Rainer Schulz ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Mitochondrial Fatty Acid
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