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Ammonia assimilation by Aspergillus nidulans: [15N]ammonia study

15N kinetic labelling studies were done on liquid cultures of wild-type Aspergillus nidulans. The labelling pattern of major amino acids under 'steady state' conditions suggests that glutamate and glutamine-amide are the early products of ammonia assimilation in A. nidulans. In the presenc...

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Main Authors: Kusnan, Misri, Klug, Klaus, Fock, Heinrich P.
Format: Article
Language:English
Published: Society for General Microbiology 1989
Online Access:http://psasir.upm.edu.my/id/eprint/39558/1/Ammonia%20Assimilation%20by%20Aspergillus%20nidulans%20%5B15N%29Ammonia%20Study.pdf
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spelling oai:psasir.upm.edu.my:39558 http://psasir.upm.edu.my/id/eprint/39558/ Ammonia assimilation by Aspergillus nidulans: [15N]ammonia study Kusnan, Misri Klug, Klaus Fock, Heinrich P. 15N kinetic labelling studies were done on liquid cultures of wild-type Aspergillus nidulans. The labelling pattern of major amino acids under 'steady state' conditions suggests that glutamate and glutamine-amide are the early products of ammonia assimilation in A. nidulans. In the presence of phosphinothricin, an inhibitor or glutamine synthetase, 15N labelling of glutamate, alanine and aspartate was maintained whereas the labelling of glutamine was low. This pattern of labelling is consistent with ammonia assimilation into glutamate via the glutamate dehydrogenase pathway. In the presence of azaserine, an inhibitor of glutamate synthase, glutamate was initially more highly labelled than any other amino acid, whereas its concentration declined. Isotope also accumulated in glutamine. Observations with these two inhibitors suggest that ammonia assimilation can occur concurrently via the glutamine synthetase/glutamate synthase and the glutamate dehydrogenase pathways in low-ammonia-grown A. nidulans. From a simple model it was estimated that about half of the glutamate was synthesized via the glutamate dehydrogenase pathway; the other half was formed from glutamine via the glutamate synthase pathway. The transfer coefficients of nine other amino acids were also determined. Society for General Microbiology 1989 Article PeerReviewed application/pdf en http://psasir.upm.edu.my/id/eprint/39558/1/Ammonia%20Assimilation%20by%20Aspergillus%20nidulans%20%5B15N%29Ammonia%20Study.pdf Kusnan, Misri and Klug, Klaus and Fock, Heinrich P. (1989) Ammonia assimilation by Aspergillus nidulans: [15N]ammonia study. Journal of General Microbiology, 135. pp. 729-738. ISSN 0022-1287 10.1099/00221287-135-4-729
institution UPM IR
collection UPM IR
language English
description 15N kinetic labelling studies were done on liquid cultures of wild-type Aspergillus nidulans. The labelling pattern of major amino acids under 'steady state' conditions suggests that glutamate and glutamine-amide are the early products of ammonia assimilation in A. nidulans. In the presence of phosphinothricin, an inhibitor or glutamine synthetase, 15N labelling of glutamate, alanine and aspartate was maintained whereas the labelling of glutamine was low. This pattern of labelling is consistent with ammonia assimilation into glutamate via the glutamate dehydrogenase pathway. In the presence of azaserine, an inhibitor of glutamate synthase, glutamate was initially more highly labelled than any other amino acid, whereas its concentration declined. Isotope also accumulated in glutamine. Observations with these two inhibitors suggest that ammonia assimilation can occur concurrently via the glutamine synthetase/glutamate synthase and the glutamate dehydrogenase pathways in low-ammonia-grown A. nidulans. From a simple model it was estimated that about half of the glutamate was synthesized via the glutamate dehydrogenase pathway; the other half was formed from glutamine via the glutamate synthase pathway. The transfer coefficients of nine other amino acids were also determined.
format Article
author Kusnan, Misri
Klug, Klaus
Fock, Heinrich P.
spellingShingle Kusnan, Misri
Klug, Klaus
Fock, Heinrich P.
Ammonia assimilation by Aspergillus nidulans: [15N]ammonia study
author_facet Kusnan, Misri
Klug, Klaus
Fock, Heinrich P.
author_sort Kusnan, Misri
title Ammonia assimilation by Aspergillus nidulans: [15N]ammonia study
title_short Ammonia assimilation by Aspergillus nidulans: [15N]ammonia study
title_full Ammonia assimilation by Aspergillus nidulans: [15N]ammonia study
title_fullStr Ammonia assimilation by Aspergillus nidulans: [15N]ammonia study
title_full_unstemmed Ammonia assimilation by Aspergillus nidulans: [15N]ammonia study
title_sort ammonia assimilation by aspergillus nidulans: [15n]ammonia study
publisher Society for General Microbiology
publishDate 1989
url http://psasir.upm.edu.my/id/eprint/39558/1/Ammonia%20Assimilation%20by%20Aspergillus%20nidulans%20%5B15N%29Ammonia%20Study.pdf
_version_ 1819296177718296576
score 13.4562235

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