Saccharomyces cerevisiae chorismate synthase has a flavin reductase activity

1996 ◽  
Vol 22 (5) ◽  
pp. 859-866 ◽  
Author(s):  
John M. Henstrand ◽  
Andreas Schaller ◽  
Martin Braun ◽  
Nikolaus Amrhein ◽  
Ju¨rg Schmid
2006 ◽  
Vol 2006 (Spring) ◽  
Author(s):  
Sonja Sollner ◽  
Sigrid Deller ◽  
Heidemarie Ehammer ◽  
Anna Prem ◽  
Peter Macheroux

2005 ◽  
Vol 71 (7) ◽  
pp. 3882-3888 ◽  
Author(s):  
Patrícia A. Ramalho ◽  
Sandra Paiva ◽  
A. Cavaco-Paulo ◽  
Margarida Casal ◽  
M. Helena Cardoso ◽  
...  

ABSTRACT Unspecific bacterial reduction of azo dyes is a process widely studied in correlation with the biological treatment of colored wastewaters, but the enzyme system associated with this bacterial capability has never been positively identified. Several ascomycete yeast strains display similar decolorizing behaviors. The yeast-mediated process requires an alternative carbon and energy source and is independent of previous exposure to the dyes. When substrate dyes are polar, their reduction is extracellular, strongly suggesting the involvement of an externally directed plasma membrane redox system. The present work demonstrates that, in Saccharomyces cerevisiae, the ferric reductase system participates in the extracellular reduction of azo dyes. The S. cerevisiae Δfre1 and Δfre1 Δfre2 mutant strains, but not the Δfre2 strain, showed much-reduced decolorizing capabilities. The FRE1 gene complemented the phenotype of S. cerevisiae Δfre1 cells, restoring the ability to grow in medium without externally added iron and to decolorize the dye, following a pattern similar to the one observed in the wild-type strain. These results suggest that under the conditions tested, Fre1p is a major component of the azo reductase activity.


2003 ◽  
Vol 31 (6) ◽  
pp. 1409-1412 ◽  
Author(s):  
A. Ponces Freire ◽  
A. Ferreira ◽  
R. Gomes ◽  
C. Cordeiro

Saccharomyces cerevisiae is an outstanding cellular model for metabolic studies in glycation. Due to its high glycolytic activity, it produces methylglyoxal, a highly reactive intracellular glycation agent, at a rate of approx. 0.1% of the glycolytic flux. We investigated methylglyoxal metabolism in Saccharomyces cerevisiae cells, using haploid null mutants. Growth studies showed that the most sensitive strains to 2-oxoaldehydes were the null mutants for GSH1 and GLO1, coding for glutathione synthase I and glyoxalase I respectively. The GRE3 null mutant, lacking aldose reductase activity, is as sensitive as the control strain. Kinetic modelling and computer simulation of this type of experiment were also performed, and we concluded that the most important parameters for controlling the intracellular concentration of methylglyoxal are the activity of glyoxalase I and the GSH concentration. Moreover, our model predicts an intracellular steady-state concentration of methylglyoxal of approx. 2 μM. Our results show that the glyoxalase pathway is the main detoxification pathway for 2-oxoaldehydes in yeast, and is likely to be the key enzymatic anti-glycation agent in these cells.


Author(s):  
M. Taran ◽  
K. Shavanova ◽  
N. Starodub

The effect of three types of nanostructured metal-containing saponite clays on brewer’s yeast, Saccharomyces cerevisiae, was investigated. The experimental data show that the studied materials, even though they possess nanometre-sized particles, do not have any inhibitory effect on organisms. In these study a significant increase in the number of cells for S. cerevisiae was demostrated. The largest concentration of cells has been recorded under the influence of a niobium-containing clay, prepared from niobium pentaethoxide at a concentration of 2 mg ml-1. Under these conditions the number of cells was increased up to 5 times in comparison to the control. According to the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test, the best results were obtained for both the proton-exchanged and niobium-containing saponite solids at a concentration of 0,5 mg ml-1. They are relatively controlled stimulate mitochondrial reductase activity of yeast cells. Исследовано влияние трех типов наноструктурированных металлосодержащих сапонитовых глин на жизнеспособность пивных дрожжей Saccharomyces cerevisiae. Экспериментальные данные показывают, что исследуемые материалы, несмотря на то, что они нанометрового размера, не проявляют ингибирующее действие на организмы. В исследовании продемонстрировано значительное увеличение количества клеток для S. cerevisiae за действия наноматериалов. Наибольшая концентрация клеток была зарегистрирована при действии нанокомпозита Nb-Sap-EtO в концентрации 2 мг/мл, в этих условиях, количество клеток было увеличено до 5 раз по сравнению с контролем. По данным МТТ теста наблюдается стимулирование активности митохондриальных редуктаз в пивных дрожжах при влиянии наноматериалов, которые содержат в своем составе ниобий в концентрациях от 0,5 мг/мл.


1991 ◽  
Vol 278 (2) ◽  
pp. 393-397 ◽  
Author(s):  
H N Truong ◽  
C Meyer ◽  
F Daniel-Vedele

Tobacco nitrate reductase (NR) produced in yeast retains cytochrome c reductase activity, but not NR activity. Biochemical data suggest that the haem and FAD domains are functional, and that the molybdenum cofactor (MoCo) domain is inactive owing to the absence of MoCo in yeast. The native form of the produced NR is dimeric. Thus MoCo is not involved in NR dimerization in higher plants, contrary to current assumptions.


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