Aerobic adaptation in yeast. IV. Alterations in enzyme synthesis during anaerobic–aerobic transitions in exponentially growing cultures

1975 ◽  
Vol 21 (6) ◽  
pp. 869-876 ◽  
Author(s):  
A. J. S. Ball ◽  
Rita M. Bruver ◽  
E. R. Tustanoff

As a corollary to the metabolite data obtained from yeast cultures undergoing an exponential anaerobic–aerobic phase transition, levels of various glycolytic and citric acid cycle enzyme activities have been monitored in these cells. The relation of the changes in these enzyme activities in cells grown on either glucose or galactose is discussed in light of different metabolic postures these cells demonstrate as a result of their transitions.A general discussion is presented which compares the results obtained in this series of papers from both step-down and exponential transfer experiments and relates these data to control of mitochondriogenesis in yeast.

2015 ◽  
Vol 53 (8) ◽  
pp. 5582-5590 ◽  
Author(s):  
Levy W. Macedo ◽  
José H. Cararo ◽  
Soliany G. Maravai ◽  
Cinara L. Gonçalves ◽  
Giovanna M. T. Oliveira ◽  
...  

2000 ◽  
Vol 182 (11) ◽  
pp. 3204-3209 ◽  
Author(s):  
Birgit Kather ◽  
Kerstin Stingl ◽  
Michel E. van der Rest ◽  
Karlheinz Altendorf ◽  
Douwe Molenaar

ABSTRACT The only enzyme of the citric acid cycle for which no open reading frame (ORF) was found in the Helicobacter pylori genome is the NAD-dependent malate dehydrogenase. Here, it is shown that in this organism the oxidation of malate to oxaloacetate is catalyzed by a malate:quinone oxidoreductase (MQO). This flavin adenine dinucleotide-dependent membrane-associated enzyme donates electrons to quinones of the electron transfer chain. Similar to succinate dehydrogenase, it is part of both the electron transfer chain and the citric acid cycle. MQO activity was demonstrated in isolated membranes of H. pylori. The enzyme is encoded by the ORF HP0086, which is shown by the fact that expression of the HP0086 sequence from a plasmid induces high MQO activity in mqo deletion mutants of Escherichia coli or Corynebacterium glutamicum. Furthermore, this plasmid was able to complement the phenotype of the C. glutamicum mqo deletion mutant. Interestingly, the protein predicted to be encoded by this ORF is only distantly related to known or postulated MQO sequences from other bacteria. The presence of an MQO shown here and the previously demonstrated presence of a 2-ketoglutarate:ferredoxin oxidoreductase and a succinyl-coenzyme A (CoA):acetoacetyl-CoA transferase indicate that H. pylori possesses a complete citric acid cycle, but one which deviates from the standard textbook example in three steps.


1970 ◽  
Vol 27 (6) ◽  
pp. 1141-1146 ◽  
Author(s):  
D. L. Liu ◽  
C. C. Walden

The caecum of the marine borer Bankia setacea was found to contain the enzymes for a modified Embden–Meyerhof pathway, a pentose cycle, and a complete citric acid cycle. The pathways are linked to the digestion of cellulose by the enzyme cellobiase. Significant numbers of bacteria were not detected in the caecum of the borer. Enzyme activities in the citric acid cycle indicate a biosynthesis role for the caecum.


2014 ◽  
Vol 25 (21) ◽  
pp. 3342-3349 ◽  
Author(s):  
Manfred Heublein ◽  
Miguel A. Burguillos ◽  
F. Nora Vögtle ◽  
Pedro F. Teixeira ◽  
Axel Imhof ◽  
...  

The mitochondrial citric acid cycle is a central hub of cellular metabolism, providing intermediates for biosynthetic pathways and channeling electrons to the respiratory chain complexes. In this study, we elucidated the composition and organization of the multienzyme complex α-ketoglutarate dehydrogenase (α-KGDH). In addition to the three classical E1-E3 subunits, we identified a novel component, Kgd4 (Ymr31/MRPS36), which was previously assigned to be a subunit of the mitochondrial ribosome. Biochemical analyses demonstrate that this protein plays an evolutionarily conserved role in the organization of mitochondrial α-KGDH complexes of fungi and animals. By binding to both the E1-E2 core and the E3 subunit, Kgd4 acts as a molecular adaptor that is necessary to a form a stable α-KGDH enzyme complex. Our work thus reveals a novel subunit of a key citric acid–cycle enzyme and shows how this large complex is organized.


1964 ◽  
Vol 46 (4) ◽  
pp. 580-596 ◽  
Author(s):  
Hartmut Brandau ◽  
Wilfried Luh

ABSTRACT The histochemical localization of some oxydative enzymes which catalize steps in the Embden-Meyerhof chain, hexosemonophosphate shunt and the citric acid cycle, was studied in normal human ovaries. In contrast to the very low concentration and homogeneous distribution of enzyme activities of the citric acid cycle in the ovarian components, the theca interna of the developing follicle and the theca and granulosa lutein cells show extremely high levels of activities of TPN-specific and glycolytic enzymes. Attempts were made to establish some relation between the findings mentioned above and the localization of hormone production. It was concluded that the synthesis of progesterone is located in the granulosa lutein cells while the formation of oestrogens takes place in the remaining ovarian components, which show a high activity of TPN-specific and glycolytic enzymes.


1973 ◽  
Vol 51 (6) ◽  
pp. 849-854 ◽  
Author(s):  
G. Lynis Dohm ◽  
Richard L. Huston ◽  
E. Wayne Askew ◽  
H. Lee Fleshood

The effects of training, exhaustive exercise, and diet on the activity of skeletal muscle citric acid cycle enzymes were studied. Training increased the activities of all cycle enzymes. Exhaustion of trained rats resulted in lowered activities of NAD-specific isocitrate dehydrogenase, succinate dehydrogenase, and cytochrome oxidase but citrate synthase and malate dehydrogenase were unaffected. The enzyme activities in untrained muscle were not changed by exhaustive exercise. High carbohydrate and high fat diets did not alter citric acid cycle activities in trained rested or untrained rested rats and did not moderate or accentuate the effects of exhaustive exercise. The results indicate that muscle citric acid cycle activity is increased by training and decreased by exhaustion of trained animals.


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