scholarly journals The unfolding and refolding of glutamate dehydrogenases from bovine liver, baker's yeast and Clostridium symbosium

1988 ◽  
Vol 251 (1) ◽  
pp. 135-139 ◽  
Author(s):  
S M West ◽  
N C Price
Keyword(s):  
Enzyme Activity ◽  
Light Scattering ◽  
Liver Enzyme ◽  
Structural Changes ◽  
Bovine Liver ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Guanidinium Chloride ◽  
Reversible Loss ◽  
Parallel Behaviour

The unfolding behaviour of the hexameric glutamate dehydrogenases from bovine liver, Clostridium symbosium and baker's yeast in solutions of guanidinium chloride (GdnHCl) was studied. Changes in Mr studied by light-scattering indicate that, in each case, the hexamer dissociates to form trimers, which then dissociate to monomers at higher concentrations of GdnHCl. Dissociation to trimers is accompanied by a reversible loss of enzyme activity, but no gross structural changes can be detected by fluorescence or c.d. Dissociation to monomers is accompanied by large structural changes, and the loss of activity cannot be reversed by dilution. The parallel behaviour of all three enzymes shows that the previously noted inability of the isolated subunits of the bovine liver enzyme to refold [Bell & Bell (1984) Biochem. J. 217, 327-330] is not a result of any modification of the enzyme as a result of import into mitochondria, since the C. symbosium and baker's-yeast enzymes do not undergo any such post-translational translocation.

scholarly journals The susceptibility towards proteolysis of intermediates during the renaturation of yeast phosphoglycerate mutase

1986 ◽  
Vol 236 (2) ◽  
pp. 617-620 ◽  
Author(s):  
C M Johnson ◽  
N C Price
Keyword(s):  
Gel Electrophoresis ◽  
Polypeptide Chain ◽  
Polyacrylamide Gel Electrophoresis ◽  
Baker’S Yeast ◽  
Polyacrylamide Gel ◽  
Phosphoglycerate Mutase ◽  
Baker's Yeast ◽  
Guanidinium Chloride ◽  
Early Stages

The renaturation of the tetrameric enzyme phosphoglycerate mutase from baker's yeast after denaturation in guanidinium chloride was studied. Three proteinases (trypsin, chymotrypsin and thermolysin) cause extensive loss of activity of samples taken during the early stages of refolding. As judged by SDS/polyacrylamide-gel electrophoresis, the proteinases cause substantial degradation of the polypeptide chain with no evidence for large quantities of fragments of Mr greater than 6500. These data suggest that the early intermediates in the refolding, especially the folded monomer, possess a number of sites that are susceptible to proteolysis.

scholarly journals Denaturation and renaturation of the monomeric phosphoglycerate mutase from Schizosaccharomyces pombe

1987 ◽  
Vol 245 (2) ◽  
pp. 525-530 ◽  
Author(s):  
C M Johnson ◽  
N C Price
Keyword(s):  
Protein Structure ◽  
Schizosaccharomyces Pombe ◽  
Baker’S Yeast ◽  
Phosphoglycerate Mutase ◽  
Rabbit Muscle ◽  
Baker's Yeast ◽  
Guanidinium Chloride ◽  
Structure And Stability

The denaturation by guanidinium chloride of the monomeric phosphoglycerate mutase from Schizosaccharomyces pombe was studied. The loss in activity broadly parallels the changes in protein structure detected by fluorescence and c.d. Renaturation can be brought about by dilution of the denaturing agent. These processes were compared with those in the enzymes from baker's yeast and rabbit muscle, which are tetrameric and dimeric respectively. The effects of the cofactor 2,3-bisphosphoglycerate on the structure and stability of the S. pombe enzyme were also investigated.

scholarly journals Effects of adenosine phosphates and nicotinamide nucleotides on pyruvate carboxylase from baker's yeast

1969 ◽  
Vol 112 (5) ◽  
pp. 755-762 ◽  
Author(s):  
J. J. Cazzulo ◽  
A. O. M. Stoppani
Keyword(s):  
Enzyme Activity ◽  
Pyruvate Carboxylase ◽  
Physiological Role ◽  
Inhibitory Effect ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Acetyl Coa ◽  
Competitive Inhibitors ◽  
Adenosine Phosphates ◽  
Regulation Of Enzyme Activity

1. Pyruvate carboxylase from baker's yeast is inhibited by ADP, AMP and adenosine at pH8·0 in the presence of magnesium chloride concentrations equal to or higher than the ATP concentration. The adenine moiety is essential for the inhibitory effect. 2. In the absence of acetyl-CoA (an allosteric activator) ADP, AMP and adenosine are competitive inhibitors with respect to ATP. In the presence of acetyl-CoA, besides the effect with respect to ATP, AMP competes with acetyl-CoA, whereas ADP and adenosine are non-competitive inhibitors with respect to the activator. 3. Pyruvate carboxylase is inhibited by NADH. The inhibition is competitive with respect to acetyl-CoA and specific with respect to NADH, since NAD+, NADP+ and NADPH do not affect the enzyme activity. In the absence of acetyl-CoA, NAD+, NADH, NADP+ and NADPH do not inhibit pyruvate carboxylase. 4. Pyruvate carboxylase is inhibited by ADP, AMP and NADH at pH6·5, in the presence of 12mm-Mg2+, 0·75mm-Mn2+ and 0·5mm-ATP, medium conditions similar to those existing inside the yeast cell. The ADP and NADH effects are consistent with a regulation of enzyme activity by the intracellular [ATP]/[ADP] ratio and secondarily by NADH concentration. These mechanisms would supplement the already known control of yeast pyruvate carboxylase by acetyl-CoA and l-aspartate. Inhibition by AMP is less marked and its physiological role is perhaps limited.

scholarly journals The significance of denaturant titrations of protein stability: a comparison of rat and baker's yeast cytochrome c and their site-directed asparagine-52-to-isoleucine mutants

1994 ◽  
Vol 299 (2) ◽  
pp. 347-350 ◽  
Author(s):  
T I Koshy ◽  
T L Luntz ◽  
B Plotkin ◽  
A Schejter ◽  
E Margoliash
Keyword(s):  
Cytochrome C ◽  
Baker’S Yeast ◽  
Site Directed Mutagenesis ◽  
Side Chain ◽  
Baker's Yeast ◽  
Guanidinium Chloride ◽  
Mutant Proteins ◽  
Cytochromes C ◽  
Structural Differences ◽  
The Stability

The residue asparagine-52 of rat cytochrome c and baker's yeast iso-1-cytochrome c was mutated to isoleucine by site-directed mutagenesis, and the unfolding of the wild-type and mutant proteins in urea or guanidinium chloride solutions was studied. Whereas the yeast mutant cytochrome unfolded in 4-7 M urea with a rate constant (k) of 1.7 x 10(-2) s-1, the rat mutant protein unfolded with k = 5.0 x 10(-2) s-1, followed by a slow partial refolding with k = 5.0 x 10(-4) s-1. Denaturant titrations indicated that the mutation increased the stability of the yeast cytochrome by 6.3 kJ (1.5 kcal)/mol, while it decreased that of the rat protein by 11.7 kJ (2.8 kcal)/mol. These results probably reflect structural differences between yeast iso-1 and vertebrate cytochromes c in the vicinity of the Asn-52 side chain.

scholarly journals Optimization of Wheat Embryo Globulin Fermenting Process and Variation in Properties during Fermentation

2019 ◽  
Vol 22 (06) ◽  
pp. 1599-1606
Author(s):  
Yi Zhao
Keyword(s):  
Free Amino ◽  
Protein Concentration ◽  
Fermentation Process ◽  
Structural Changes ◽  
Baker’S Yeast ◽  
Yeast Fermentation ◽  
Baker's Yeast ◽  
Food Ingredient ◽  
Wheat Embryo ◽  
Nutritional Characteristics

In this study, an efficient preparation technology of fermented wheat embryo globulin (FWEG) was developed, and the changes of nutritional characteristics and structure of FWEG were studied during the fermentation process. Protein concentration was selected as the evaluation index, and Box-Behnken experiment design was employed for optimizing the preparation conditions of FWEG. The nutritional characteristics of FWEG during fermentation were dissected through SDSPAGE and free amino acid assay. The structural changes of FWEG during fermentation were analyzed through circular dichroism, sulfhydryl detection, and electron microscope scanning. The optimum fermentation conditions were determined. The protein concentration of FWEG reached 2.09 ± 0.15 mg mL-1 under the optimal conditions. Acidity, contents of protein and protease increased while the content of FWEG decreased in the fermentation. The concentration of small molecule protein and free amino acids went up along with the fermentation. Due to changes in the secondary structure of FWEG and massive released of sulfhydryl groups, the surface of FWEG became uneven during the fermentation. The optimal fermentation process was noticed after Baker's yeast fermentation, lasting for 3.2 h; Lactobacillus plantarum was inoculated, and the fermentation continuous for 14.8 h, in which the ratio of baker's yeast to L. plantarum (V:V) was 1:2. The nutritional quality of wheat embryo globulin was improved, and its structure was changed during fermentation, which increased the absorption of FWEG and enhanced its suitability as a food ingredient. © 2019 Friends Science Publishers

COD REDUCTION OF BAKER'S YEAST WASTEWATER USING BATCH ELECTROCOAGULATION

2014 ◽  
Vol 13 (12) ◽  
pp. 3153-3160 ◽  
Author(s):  
Zakaria Al-Qodah ◽  
Mohammad Al-Shannag ◽  
Kholoud Alananbeh ◽  
Nahla Bouqellah ◽  
Eman Assirey ◽  
...  
Keyword(s):  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Cod Reduction ◽  
Yeast Wastewater
Sign in / Sign up

Export Citation Format

Share Document