Hogness and Mitchell (1954) initially reported that the level of Neurospora crassa tryptophan synthetase increased in a histidine auxotroph grown under conditions of histidine limitation. Carsiotis and Lacy (1965) then observed that levels of this enzyme, and another Trp biosynthetic enzyme, indole glycerol phosphate synthetase, increased in a variety of different His- mutants that were starved for His (Carsiotis and Lacy 1965). By 1974, it was established that either His or Trp starvation resulted in elevation of enzymes involved in Arg, His and Trp biosynthesis (Carsiotis and Jones 1974; Carsiotis et al. 1974). These studies demonstrated that addition of 3AT (3-amino-1,2,4triazole) to cultures resulted in His starvation. They introduced the concept of cross-pathway control (Carsiotis and Jones 1974) to describe “[the] phenomenon wherein starvation for a single amino acid causes derepression of biosynthetic enzymes of other amino acids as well as those of the deficient amino acid.” A similar phenomenon observed in Saccharomyces cerevisiae became known as the general control of amino acid biosynthesis (Guerzoni 1972; Schurch et al. 1974; Delforge et al. 1975; Wolfner et al. 1975).

General and Cross-Pathway Controls of Amino Acid Biosynthesis

summary
In order to determine significance of the glutamate dehydrogenase pathway and a glutamine synthetase/glutamate synthase cycle in NH4+ assimilation, we followed a number of different metabolikc parameters (nutrient uptake, free amino acid pools, NH4+-induced glutamine accumulation) and 15N incorporation into amino acids of rapidly growing Cennoccum geophilum. Arginine was a major free amino acid in C. geophilum during its entire growth period. C. geophilum synthesized and accumulated very large amounts of glutamine at the beginning of the rapid phase of growth in low nitrogen medium, during the whole growth period in high nitrogen medium, and immediately after addition of NH4+. Therefore, the accumulation of a large amount of glutamine tool; place when the external ammonium concentration was high. The current data identify four pathways of N metabolism in rapidly growing C. geophilum: (1) glutamine synthesis, invoking transfer of N to both amino and amino moieties; (2) glutamate formation; (3) transamination with pyruvate to yield alanine; (4) transamination with oxaloacetate to yield asparate. The higher accumulation of glutamate and related amino acids (alanine and aspartate) in the presence of the glutamine synthetase inhibitor methionine sulphoximine indicates that glutamate, the precursor of glutamine, was formed by a pathway insensitive to methionine sulphoximine, the glutamate dehydrogenase pathway. Up to 40% of the assimilated 15N terminated in the amido-N of glutamine. These data are consistent with a pivotal role for glutamine synthetase activity and indicates that the primary assimilation of NH4+ in rapidly growing C. geophilum is brought about by concurrent activity of the GDH and GS pathways. The pathway of primary assimilation of NH4+ by C. geophilunt in the rapid phase of growth therefore differs from those operating in the stationary phase of growth where N flax through GDH is higher than the flux through the GS pathway.

The involvement of glutamate dehydrogenase and glutamine synthetase in ammonia assimilation by the rapidly growing ectomycorrhizal ascomycete, Cenococcum geophilum Fr.

SUMMARY: Wild-type Aspergillus nidulans grew equally well on NH4Cl, KNO3 or glutamine as the only nitrogen source. NADP+-dependent glutamate dehydrogenase (EC 1.4.1.4) and glutamine synthetase (GS; EC 6.3.1.2) activities varied with the type and concentration of nitrogen source supplied. Glutamate synthase (GOGAT) activity (EC 1.4.7.1) was detected but it was almost unaffected by the type and concentration of nitrogen source supplied. Ion exchange chromatography showed that the GOGAT activity was due to a distinct enzyme. Azaserine, an inhibitor of the GOGAT reaction, reduced the glutamate pool by 60%, indicating that GOGAT is involved in ammonia assimilation by metabolizing the glutamine formed by GS.

The involvement of glutamine synthetase/glutamate synthase in ammonia assimilation by Aspergillus nidulans.

A fungal strain, Penicillium purpurogenum IAM 15392, produced the azaphilone Monascus pigment homolog when cultured in a medium composed of soluble starch, ammonium nitrate, yeast extract, and citrate buffer, pH 5.0. One of the typical features of violet pigment PP-V [(10Z)-12- carboxyl-monascorubramine] is that pyranoid oxygen is replaced with nitrogen. In this study, we found that glutamine synthetase (glnB) and glutamate dehydrogenase (gdh1) genes were expressed in the culture conditions conducive to PP-V production. Gln and Glu both support PP-V biosynthesis, but PP-V biosynthesis was much more efficient with Gln. We determined that synthesis of Gln by glutamine synthetase from ammonium is important for PP-V production.

/pdf/importance-of-the-ammonia-assimilation-by-penicillium-11767ikdhf.pdf

Importance of the ammonia assimilation by Penicillium purpurogenum in amino derivative Monascus pigment, PP-V, production

Summary: When grown on ammonia as sole nitrogen source, the basidiomycete fungus Stropharia semiglobata assimilated nitrogen via glutamate dehydrogenase (GDH). The two isoenzymes of GDH were both repressed by increasing concentrations of ammonia, but NADP-GDH (EC 1.4.1.4) was far more active than NAD-GDH (EC 1.4.1.2). Glutamine synthetase (GS; EC 6.3.1.2) and glutamate synthase (GOGAT; EC 1.4.7.1) were also active in S. semiglobata and these enzyme activities were independent of the ammonia concentration in the suspension. From enzyme activity and 1 5N-labelling studies of amino acids, it is concluded that both GDH and GS/GOGAT contribute to ammonia assimilation in this fungus.

/pdf/the-involvement-of-glutamate-dehydrogenase-and-glutamine-s9rl98fpel.pdf

The involvement of glutamate dehydrogenase and glutamine synthetase/glutamate synthase in ammonia assimilation by the basidiomycete fungus Stropharia semiglobata

Activities of ammonia-metabolizing enzymes from Candida maltosa were measured. The synthesis of glutamate and glutamine involves three primary enzymes: glutamate dehydrogenase (GDH), glutamine synthetase (GS), and glutamate synthase (GOGAT). This yeast has two distinct GDH, the first responsible for glutamate catabolism, and the second solely biosynthetic. The GS is derepressed during growth on low ammonia or on a variety of alternative nitrogen sources, whereas the catabolic GDH (NAD) is repressed under this conditions. Ammonia limitation did not significantly affect GOGAT as well as biosynthetic GDH (NADP) levels. The relatively low Km-value for ammonia suggest that the GS is catalytically active during cell growth on low concentrations of ammonia. It seems that under N-limitation ammonia assimilation is achieved via GS/GOGAT and under N-excess via GDH/GS.

Untersuchungen zur Regulation der Ammoniumassimilation von Candida maltosa

The general control of amino acid biosynthesis was investigated in Candida spec. EH 15/D, using single and double mutant auxotrophic strains and prototrophic revertants starved for their required amino acids. These experiments show that starvation for lysine, histidine, arginine, leucine, threonine, proline, serine, methionine, homoserine, asparagine, glutamic acid or aspartic acid can result in derepression of enzymes. A correlation was found between the degree of derepression, growth of strains, and concentration of required amino acids. The amino acids pcol pattern of mutants and revertants is different from that in the wild type strain.

Allgemeine Kontrolle der Aminosäurebiosynthese in Mutanten von Candida spec. EH 15/D

Candida maltosa mutants deficient in the metabolism of glutamate aspartate were isolated One of these mutants required asparagine, the second asparagine or aspartate, and the third grew with various amino acids (glutamate, glutamine, aspartate, asparagine, proline, arginine, ornithine, or lysine) or excess of ammonia The biochemical defects were as follows: asparagine synthetase (asn1), aspartate aminotransferase (asp1), and glutamate synthase (glu1) On the basis of these data and additional biochemical studies we suggest that glutamate synthase is required for the assimilation of ammonia, and that glutamate dehydrogenase may be involved in glutamate production only in the presence of excess of ammonia Aspartate is only synthesized from glutamate via transamination, while the synthesis of asparagine from aspartate is catalyzed by an asparagine synthetase

Untersuchungen zum Glutamat/Aspartat-Metabolismus von Candida maltosa

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

P. Casper

Author Tools

Chat about Author

Papers

Untersuchungen zur Regulation der Ammoniumassimilation von Candida maltosa

Allgemeine Kontrolle der Aminosäurebiosynthese in Mutanten von Candida spec. EH 15/D

Untersuchungen zum Glutamat/Aspartat-Metabolismus von Candida maltosa