Document Detail


Changes in free amino acid content and activities of amination and transamination enzymes in yeasts grown on different inorganic nitrogen sources, including hydroxylamine.
MedLine Citation:
PMID:  6115616     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study concerns inter- and intraspecific differences between yeasts at assimilation of different nitrogen sources. Alterations in the content of free amino acids in cells and media as well as in the related enzyme activities during growth were studied. The hydroxylamine (HA)-tolerant Endomycopsis lipolytica was examined and compared with the nitrate-reducing Cryptococcus albidus, and Saccharomyces cerevisiae, requiring fully reduced nitrogen for growth. Special attention was paid to alanine, aspartic acid, and glutamic acid, the amino acids closely related to the Krebs cycle keto acids. The amino acids were analyzed as their n-propyl N-acetyl esters by gas-liquid chromatography (GLC). The composition of the amino acid pool was similar for the three yeasts. Glutamic acid was predominant; in early log-phase cells of E. lipolytica contents of 200-234 micromol . g(-1) dry weight were found. A positive correlation between the specific growth rate and the size of the amino acid pool was observed. The assimilation of ammonia was mediated by glutamate dehydrogenase (GDH). The NADP-GDH was the dominating enzyme in all three yeasts showing the highest specific activity in Cr. albidus grown on nitrate (6980 nmol . (min(-1)).(mg protein(-1)). Glutamine synthetase (GS) displayed a high specific activity in S. cerevisiae, which also had a high amount of glutamine. The assimilation of HA did not differ greatly from the assimilation of ammonium in E. lipolytica. The existing differences could rather be explained as provoked by the concentration of available nitrogen.
Authors:
B Norkrans; I Tunblad-Johansson
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Antonie van Leeuwenhoek     Volume:  47     ISSN:  0003-6072     ISO Abbreviation:  Antonie Van Leeuwenhoek     Publication Date:  1981  
Date Detail:
Created Date:  1981-10-14     Completed Date:  1981-10-14     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0372625     Medline TA:  Antonie Van Leeuwenhoek     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  217-30     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Alanine Transaminase / metabolism
Amino Acids / metabolism*
Ascomycota / metabolism*
Aspartate Aminotransferases / metabolism
Cryptococcus / metabolism*
Glutamate Dehydrogenase / metabolism
Glutamate-Ammonia Ligase / metabolism
Hydroxylamines / metabolism
Saccharomyces cerevisiae / metabolism*
Saccharomycetales / metabolism*
Species Specificity
Chemical
Reg. No./Substance:
0/Amino Acids; 0/Hydroxylamines; EC 1.4.1.2/Glutamate Dehydrogenase; EC 2.6.1.1/Aspartate Aminotransferases; EC 2.6.1.2/Alanine Transaminase; EC 6.3.1.2/Glutamate-Ammonia Ligase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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