• Title/Summary/Keyword: Proteolysis

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Enhancement of human serum albumin production in Saccharomyces cerevisiae

  • Seo, Dong-Sik;Choi, Byung-Hyun;Kang, Whan-Koo;Kim, In-Ho;Hong, Eock-Kee
    • 한국생물공학회:학술대회논문집
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    • 2001.11a
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    • pp.767-770
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    • 2001
  • Experiments were accomplished to reduce the extent of proteolysis by simply controlling the culture conditions instead of the gene manipulation techniques. L-arginine and L-lysine were chosen as a protease inhibitor analogue With the assumption that they might act as the potential inhibitors against proteases involved in the rHSA proteolysis. The addition of arginine and lysine resulted in a considerable positive effect on the secreted rHSA production level.

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Control of asymmetric cell division in early C. elegans embryogenesis: teaming-up translational repression and protein degradation

  • Hwang, Sue-Yun;Rose, Lesilee S.
    • BMB Reports
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    • v.43 no.2
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    • pp.69-78
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    • 2010
  • Asymmetric cell division is a fundamental mechanism for the generation of body axes and cell diversity during early embryogenesis in many organisms. During intrinsically asymmetric divisions, an axis of polarity is established within the cell and the division plane is oriented to ensure the differential segregation of developmental determinants to the daughter cells. Studies in the nematode Caenorhabditis elegans have contributed greatly to our understanding of the regulatory mechanisms underlying cell polarity and asymmetric division. However, much remains to be elucidated about the molecular machinery controlling the spatiotemporal distribution of key components. In this review we discuss recent findings that reveal intricate interactions between translational control and targeted proteolysis. These two mechanisms of regulation serve to carefully modulate protein levels and reinforce asymmetries, or to eliminate proteins from certain cells.

Effect of Ripening Period, Nitrite Level and Heat Treatment on the Chemical Characteristics of Turkish Dry Fermented Sausage (Sucuk)

  • Kurt, Sukru;Zorba, Omer
    • Asian-Australasian Journal of Animal Sciences
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    • v.23 no.8
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    • pp.1105-1111
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    • 2010
  • In order to determine the potential for reduction of nitrite levels and ripening period with heat treatment, the effects of ripening period (1-13 days), nitrite level (45-195 ppm), and heat treatment (30-$90^{\circ}C$) on lipolysis, peroxide, TBA, proteolysis, and residual nitrite values of sucuk were investigated using response surface methodology. The ripening period significantly (p<0.01) increased lipolysis, peroxide, TBA, and proteolysis values and decreased residual nitrite values. The effects of additional nitrite levels were found to significantly affect peroxide and residual nitrite values. Significant amounts of the additional nitrite levels were reduced during processing and on the first day of ripening periods.

Metastasis-associated Factors Facilitating the Progression of Colorectal Cancer

  • Zhang, Yao-Yao;Chen, Bin;Ding, Yan-Qing
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.6
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    • pp.2437-2444
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    • 2012
  • Tumor metastasis remains the principal cause of treatment failure and poor prognosis in patients with colorectal cancer. It is a multistage process which includes proteolysis, motility and migration of cells, proliferation in a new site, and neoangiogenesis. A crucial step in the process of intra- and extra-vasation is the activation of proteolytic enzymes capable of degrading the extracellular matrix (ECM). In this stage, urokinase plasminogen activator receptor (uPAR) and matrix metalloproteinases (MMPs) are necessary. Micrometastases need the presence of growth factor and vascular growth factor so that they can form macrometastasis. In addition, cell adhesion molecules (CAMs) and guanine nucleotide exchange factors (GEFs) play important roles in the progression of colorectal cancer and metastatic migration. Further elucidation of the mechanisms of how these molecules contribute will aid in the identification of diagnostic and prognostic markers as well as therapeutic targets for patients with colorectal metastasis.

Proteolysis of the Reverse Transcriptase of Hepatitis B Virus by Lon Protease in E. coli

  • Han, Joo-Seok;Park, Jae-Yong;Hwang, Deog-Su
    • Animal cells and systems
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    • v.5 no.3
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    • pp.195-198
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    • 2001
  • Hepatitis B virus (HBV) polymerase, which possesses the activities of terminal binding, DNA polymerase, reverse transcriptase and RNaseH, has been shown to accomplish viral DNA replication through a pregenomic intermediate. Because the HBV polymerase has not been purified, the expression of HBV polymerase was examined in an E. coli expression system that is under the regulation of arabinose operon. The expressed individual domain containing terminal binding protein, polymerase, or RNaseH turned out to be insoluble. The activities of those domains were not able to be recovered by denaturation and renaturation using urea or guanidine-HCI. The expressed reverse transcriptase containing the polymerase and RNaseH domains became extensively degraded, whereas the proteolysis was reduced in a Ion- mutant. These results indicate that Lon protease proteolyzes the HBV reverse transcriptase expressed in E. coli.

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Crosstalk and Interplay between the Ubiquitin-Proteasome System and Autophagy

  • Ji, Chang Hoon;Kwon, Yong Tae
    • Molecules and Cells
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    • v.40 no.7
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    • pp.441-449
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    • 2017
  • Proteolysis in eukaryotic cells is mainly mediated by the ubiquitin (Ub)-proteasome system (UPS) and the autophagy-lysosome system (hereafter autophagy). The UPS is a selective proteolytic system in which substrates are recognized and tagged with ubiquitin for processive degradation by the proteasome. Autophagy is a bulk degradative system that uses lysosomal hydrolases to degrade proteins as well as various other cellular constituents. Since the inception of their discoveries, the UPS and autophagy were thought to be independent of each other in components, action mechanisms, and substrate selectivity. Recent studies suggest that cells operate a single proteolytic network comprising of the UPS and autophagy that share notable similarity in many aspects and functionally cooperate with each other to maintain proteostasis. In this review, we discuss the mechanisms underlying the crosstalk and interplay between the UPS and autophagy, with an emphasis on substrate selectivity and compensatory regulation under cellular stresses.