The anaerobic fungus Piromyces sp. strain E2: nitrogen requirement and enzymes involved in primary nitrogen metabolism.
The anaerobic fungus Piromyces sp. strain E2 appeared restricted in nitrogen utilization. Growth was only supported by ammonium as source of nitrogen. Glutamine also resulted in growth, but this was due to release of ammonia rather than to uptake and utilization of the amino acid. The fungus was not able to grow on other amino acids, albumin, urea, allantoin, or nitrate. Assimilation of ammonium is very likely to be mediated by NADP-linked glutamate dehydrogenase (NADP-GDH) and glutamine synthetase (GS). One transaminating activity, glutamate-oxaloacetate transaminase (GOT), was demonstrated. Glutamate synthase (GOGAT), NAD-dependent glutamate dehydrogenase (NAD-GDH), and the transaminating activity glutamate-pyruvate transaminase (GPT) were not detected in cell-free extracts of Piromyces sp. strain E2. Specific enzyme activities of both NADP-GDH and GS increased four- to sixfold under nitrogen-limiting conditions.
Dijkerman
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R
Department of Microbiology and Evolutionary Biology, Faculty of Science, University of Nijmegen, Toernooiveld 1, NL-6525 ED Nijmegen, The Netherlands. rem@sci.kun.nl
Ledeboer
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Verhappen
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den Camp
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der Drift
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Vogels
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D000418:Albumins / Q000378:metabolism; D000481:Allantoin / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism; D000641:Ammonia / Q000378:metabolism; D000693:Anaerobiosis; D005658:Fungi / Q000201:enzymology* / Q000378:metabolism*; D005969:Glutamate Dehydrogenase / Q000378:metabolism; D005970:Glutamate Synthase / Q000378:metabolism; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D000637:Transaminases / Q000378:metabolism; D014508:Urea / Q000378:metabolism
D000418:Albumins; D000596:Amino Acids; D009573:Nitrites; D000644:Quaternary Ammonium Compounds; D005973:Glutamine; D009243:NAD; D000481:Allantoin; D000641:Ammonia; D014508:Urea; D005970:Glutamate Synthase; D005969:Glutamate Dehydrogenase; D000637:Transaminases; C020656:glutamine-pyruvate aminotransferase; D005974:Glutamate-Ammonia Ligase; D009584:Nitrogen