Dual effect of amino acids on the development of intracellular proteolytic activity in the irreversible sporulation phase ofBacillus megaterium

1994 ◽  
Vol 28 (6) ◽  
pp. 345-349 ◽  
Author(s):  
Helena Kučerová ◽  
Marie Strnadová ◽  
Vladimír Vinter ◽  
Jaroslav Votruba ◽  
Jiří Chaloupka
Keyword(s):  
Amino Acids ◽  
Proteolytic Activity ◽  
Dual Effect ◽  
Sporulation Phase

THE PROTEOLYTIC ACTIVITY OF INSULIN

1967 ◽  
Vol 45 (9) ◽  
pp. 1329-1333
Author(s):  
Michel Page ◽  
Claude Godin
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Proteolytic Activity ◽  
Protein Amino Acids

The action of insulin on hemoglobin at pH 7.5 was studied. Four different methods were used to determine the degree of proteolysis. After mixtures of hemoglobin and insulin were incubated for 2 hours, very little amino acid or peptide material was liberated from the proteins. As many amino acids are liberated from hemoglobin when it is incubated alone under the same conditions. It is concluded that autolysis is responsible for the observed increases in non-protein amino acids and that insulin has no proteolytic activity under the conditions used in this study.

Diversity in growth and protein degradation by dairy relevant lactic acid bacteria species in reconstituted whey

2012 ◽  
Vol 79 (2) ◽  
pp. 201-208 ◽  
Author(s):  
Micaela Pescuma ◽  
Elvira M. Hébert ◽  
Elena Bru ◽  
Graciela Font de Valdez ◽  
Fernanda Mozzi
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Protein Degradation ◽  
Proteolytic Activity ◽  
Starter Culture ◽  
Whey Proteins ◽  
Principal Component ◽  
Fermented Foods ◽  
Small Peptides

The high nutritional value of whey makes it an interesting substrate for the development of fermented foods. The aim of this work was to evaluate the growth and proteolytic activity of sixty-four strains of lactic acid bacteria in whey to further formulate a starter culture for the development of fermented whey-based beverages. Fermentations were performed at 37°C for 24 h in 10 and 16% (w/v) reconstituted whey powder. Cultivable populations, pH, and proteolytic activity (o-phthaldialdehyde test) were determined at 6 and 24 h incubation. Hydrolysis of whey proteins was analysed by Tricine SDS-PAGE. A principal component analysis (PCA) was applied to evaluate the behaviour of strains. Forty-six percent of the strains grew between 1 and 2 Δlog CFU/ml while 19% grew less than 0·9 Δlog CFU/ml in both reconstituted whey solutions. Regarding the proteolytic activity, most of the lactobacilli released amino acids and small peptides during the first 6 h incubation while streptococci consumed the amino acids initially present in whey to sustain growth. Whey proteins were degraded by the studied strains although to different extents. Special attention was paid to the main allergenic whey protein, β-lactoglobulin, which was degraded the most byLactobacillus acidophilusCRL 636 andLb. delbrueckiisubsp.bulgaricusCRL 656. The strain variability observed and the PCA applied in this study allowed selecting appropriate strains able to improve the nutritional characteristics (through amino group release and protein degradation) and storage (decrease in pH) of whey.

A study on the degradation of arachin by proteolytic enzymes

1973 ◽  
Vol 51 (11) ◽  
pp. 2217-2222 ◽  
Author(s):  
R. B. van Huystee
Keyword(s):  
Amino Acids ◽  
Proteolytic Activity ◽  
Free Amino Acids ◽  
Free Amino ◽  
Proteolytic Enzymes ◽  
Disc Electrophoresis ◽  
Polyacrylamide Gels ◽  
Macromolecular Protein

The prime purpose of this proteolysis study was to direct attention to alternate means of measuring proteolytic activity other than the determination of free amino acids. The release of peptides from a macromolecular protein during incubation with either papain, pronase, or trypsin was determined by measuring the presence of 280-nm-absorbing molecules in the fractionation range of Sephadex G 25 eluant after incubation. The formation of larger proteinaceous constituents by proteolysis of arachin was analyzed by disc electrophoresis on polyacrylamide gels. Using these techniques it was noted that papain was the most efficient proteolytic agent for the degradation of arachin.

scholarly journals Inducible degradation of I kappa B alpha in vitro and in vivo requires the acidic C-terminal domain of the protein.

1995 ◽  
Vol 15 (5) ◽  
pp. 2413-2419 ◽  
Author(s):  
M S Rodriguez ◽  
I Michalopoulos ◽  
F Arenzana-Seisdedos ◽  
R T Hay
Keyword(s):  
Amino Acids ◽  
Proteolytic Activity ◽  
Cell Activation ◽  
Nf Kappa B ◽  
Free System ◽  
In Vitro System ◽  
I Kappa B Alpha ◽  
Terminal Domain

After exposure of cells to tumor necrosis factor (TNF), I kappa B alpha is rapidly degraded by a proteolytic activity that is required for nuclear localization and activation of transcription factor NF-kappa B. To investigate this problem, we have developed a cell-free system to study the degradation of I kappa B alpha initiated in vivo. In this in vitro system, characteristics of endogenous I kappa B alpha degradation were comparable to those observed in vivo. Recombinant I kappa B alpha, when added to lysates from cells exposed to TNF, was specifically degraded by a cellular proteolytic activity; however, it was stable in extracts from unstimulated cells. Inhibition characteristics of the proteolytic activity responsible for I kappa B alpha degradation suggest the involvement of a serine protease. Analysis of mutated forms of I kappa B alpha in the in vitro system demonstrated that an I kappa B alpha species which was unable to interact with NF-kappa B was still efficiently degraded. In contrast, deletion of the C-terminal 61 amino acids from I kappa B alpha rendered the protein resistant to proteolytic degradation. Expression of I kappa B alpha mutated forms in COS-7 cells confirmed the importance of the C-terminal domain for the degradation of the protein in vivo following cell activation. Thus, it is likely that the acidic, negatively charged region represented by the C-terminal 61 amino acids of the protein contains residues critical for TNF-inducible degradation of I kappa B alpha.

scholarly journals The localization of proteolytic activity in rat liver mitochondria and its relation to mitochondrial swelling and aging

1969 ◽  
Vol 111 (5) ◽  
pp. 763-776 ◽  
Author(s):  
K. G. M. M. Alberti ◽  
W. Bartley
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Proteolytic Activity ◽  
Rat Liver ◽  
Acid Production ◽  
Liver Mitochondria ◽  
Ground Substance ◽  
Rat Liver Mitochondria ◽  
Amino Acid Production ◽  
Freezing And Thawing

1. On storage of rat liver mitochondria at 0°, water content, total amino acid content and leakage of protein all rose steadily over a 72hr. period. The initial ratio of intramitochondrial to extramitochondrial amino acid concentration lay between 18 and 24. Initially this rose, but it then fell to 1·9 at the end of storage. The concentration gradient between internal and external amino acids was relatively constant throughout the period. These processes were accentuated at 22° and 40°, the concentration gradient reaching 70μmoles/ml., water content rising to 8·3mg./mg. dry wt. and protein leakage reaching 42% of total mitochondrial protein. ‘Swelling agents’ produced no correlated changes in amino acid production and swelling. 2. Added glutamate was not concentrated within the pellet of whole or disrupted mitochondria. Endogenous amino acids were distributed evenly between the pellet and the supernatant of disrupted mitochondria. It is concluded that amino acids are produced within mitochondria and that adsorption and uptake from the medium do not contribute significantly to amino acids in the pellet. 3. β-Glycerophosphate, a lysosome protectant, increased amino acid production by rat liver mitochondria. Treatment with Triton X-100 and disruption by freezing and thawing showed that 56% of proteolytic activity was ‘free’ in whole mitochondria, whereas only 11% of acid phosphatase activity, a lysosomal enzyme, was ‘free’. 4. ‘Light’ mitochondria contained 30% more neutral proteolytic activity but 300% more acid phosphatase activity than ‘heavy’ mitochondria. 5. Electron micrographs of mitochondrial preparations showed less than one particle in 500 that could be identified as a lysosome. Treatment with Triton X-100 disrupted the structure of roughly 50% of the mitochondria; the rest appeared to retain their membrane, cristae and ground substance. Freezing and thawing caused gross swelling and loss of ground substance and rupture of external membranes. 6. Of the recovered proteolytic activity, 81% at pH7·4 and 70% at pH5·8 were found in the high-speed supernatant of broken mitochondria. A further fivefold increase in specific activity was found in the first protein fraction obtained by Sephadex G-50 gel filtration. 7. Between 60 and 80% of proteolytic activity was found in the 40–60%-saturated ammonium sulphate precipitate. Almost all of the soluble-fraction proteolytic activity could be recovered in a pH5·0 supernatant. 8. The results give no support to the view that mitochondrial neutral proteolytic activity reflects lysosomal content. 9. The possible role of intramitochondrial amino acid production and the proteolysis of internal barriers in passive swelling of mitochondria is discussed.

INCORPORATION OF AMINO ACIDS INTO CHICK PROTEINS DURING EMBRYONIC GROWTH

1965 ◽  
Vol 43 (7) ◽  
pp. 1099-1110 ◽  
Author(s):  
Margaret P. Taussig
Keyword(s):  
Amino Acids ◽  
Proteolytic Activity ◽  
Specific Activity ◽  
Sharp Decrease ◽  
Embryonic Growth

Radioactive glycine and methionine were injected into the yolk of 4-day-old embryonated eggs. There was a rapid increase in total incorporated radioactivity with both amino acids. The specific activity of the protein increased until the seventh day, after which time there was a sharp decrease. Radioactivity from DL-methionine-S35 was incorporated in larger amounts than from glycine-2-C14. An increase in the proteolytic activity of the yolk with age was demonstrated.

N-terminal Glycine Analysis for the Determination of the Proteolytic Activity of Thrombin

1960 ◽  
Vol 04 (02) ◽  
pp. 167-177
Author(s):  
Staffan Magnusson
Keyword(s):  
Amino Acids ◽  
Proteolytic Activity ◽  
Standard Method ◽  
Terminal Position ◽  
Thrombin Activity ◽  
Chemical Determination ◽  
Terminal Amino ◽  
Good Agreement

SummaryIn the method presented in this paper for the assay of thrombin activity, N-terminal amino acids are determined with the phenylisothiocyanate method of Edman. Highly purified bovine fibrinogen is proteolyzed by thrombin under strictly defined conditions. The increase in N-terminal glycine is then directly proportional to the activity of the thrombin. Five different thrombin preparations were standardized with this N-terminal method and with a clotting method. The results obtained with the two methods are in good agreement. Because the N-terminal method is accurate and highly specific for thrombin it is proposed as standard method for the chemical determination of thrombin activity. One NIH unit of thrombin was found to make 0.4 μimoles of glycine appear in N-terminal position.

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