Influence of NH4CI on Polarized Release of Endogenous Protein Degradation Products and on Morphology in LLC-PK1 Cells

2000 ◽  
Vol 20 (1) ◽  
pp. 74-81 ◽  
Author(s):  
Eva Wardelmann ◽  
Hong Ling ◽  
Inge Heim ◽  
Harald Schlebusch ◽  
August Heidland ◽  
...  
Keyword(s):  
Protein Degradation ◽  
Degradation Products ◽  
Endogenous Protein

THE DETERMINATION OF TERMINAL PROTEIN-BOUND FUCOSE

1965 ◽  
Vol 43 (11) ◽  
pp. 1807-1811 ◽  
Author(s):  
G. Gyorky ◽  
J. C. Houck
Keyword(s):  
Protein Degradation ◽  
Spectrophotometric Determination ◽  
Trichloroacetic Acid ◽  
Degradation Products ◽  
Dilute Acid ◽  
Terminal Protein ◽  
Residual Protein ◽  
Color Yield ◽  
Fucose Content

The spectrophotometric determination of protein-bound fucose is badly compromised by spurious chromagens developed from protein degradation products. To minimize the contribution of these spurious products to the color yield of fucose, the glycoprotein was partially hydrolyzed in dilute acid, thus releasing the terminal carbohydrate from the protein moieties, and the residual protein was removed with trichloroacetic acid. That the fucose content of this supernatant was real was confirmed by paper chromatography and spectral studies.The spurious chromagens were shown to result from the interaction of protein degradation products and galactose.

Mechanisms of calcium disposal from osteoclastic resorption hemivacuole

2003 ◽  
Vol 176 (1) ◽  
pp. 1-5 ◽  
Author(s):  
HK Datta ◽  
BR Horrocks
Keyword(s):  
Protein Degradation ◽  
Experimental Evidence ◽  
Matrix Protein ◽  
Degradation Products ◽  
Transcellular Transport ◽  
Osteoclastic Resorption ◽  
Osteoclast Function ◽  
Theoretical Considerations ◽  
Simple Link

One of the most remarkable but neglected aspects of osteoclast function is its unique adaptation that allows the cell to function despite its resorbing surface being exposed to extremely high levels of ambient Ca2+. Recently our studies have provided evidence of continuous transcellular Ca2+ disposal, suggesting that osteoclasts are able to prevent Ca2+ accumulation within the resorptive hemivacuole. It has also been shown that matrix protein degradation products that accumulate within the osteoclast resorptive vacuole are also undergoing transcellular transport by transcytosis. However, both experimental evidence and theoretical considerations suggest that transcellular transport of Ca2+ and matrix protein is likely to occur via distinct routes. In light of these considerations, we are able to provide convincing explanations for the apparent anomalies of osteoclast intracellular [Ca2+] responses to a variety of endocrine stimuli. The understanding of the mechanisms involved in Ca2+ handling by osteoclasts indicates the lack of a simple link between osteoclast function and changes in overall cytosolic [Ca2+].

scholarly journals Both endocytic and endogenous protein degradation in fibroblasts is stimulated by serum/amino acid deprivation and inhibited by 3-methyladenine

1990 ◽  
Vol 272 (3) ◽  
pp. 577-581 ◽  
Author(s):  
K B Hendil ◽  
A M B Lauridsen ◽  
P O Seglen
Keyword(s):  
Amino Acid ◽  
Protein Degradation ◽  
Protein A ◽  
Fold Increase ◽  
Isolated Hepatocytes ◽  
Lysosomal Degradation ◽  
Endogenous Protein ◽  
Endocytic Protein ◽  
Deficient Medium ◽  
Epidermal Growth

Incubation of BHK-21 hamster fibroblasts in a serum- and amino acid-deficient medium caused a 3-fold increase in the degradation of endogenous protein, a doubling of the degradation of endocytosed epidermal growth factor, and an eightfold increase in the degradation of endocytosed alpha 2-macroglobulin. 3-Methyladenine (3MA) inhibited the deprivation-induced lysosomal degradation of both endogenous and endocytosed protein, but had no effect on basal (non-induced) degradation. 3MA also inhibited deprivation-induced protein degradation in human IMR-90 fibroblasts. Some inhibition of protein synthesis and of endocytic uptake of alpha 2-macroglobulin was observed in 3MA-treated BHK-21 cells, whereas cellular ATP levels were unaffected. These results are different from those obtained with isolated hepatocytes, and suggest that in some cells both endogenous and endocytic protein degradation may be accelerated as part of a general deprivation response.

scholarly journals Rapid and efficient adaptation of the dTAG system in mammalian development reveals stage specific requirements of NELF

2021 ◽  
Author(s):  
Abderhman Abuhashem ◽  
Anna-Katerina Hadjantonakis
Keyword(s):  
Protein Degradation ◽  
Protein Function ◽  
Mammalian Cell Culture ◽  
Elongation Factor ◽  
Model Systems ◽  
Mammalian Development ◽  
Endogenous Protein ◽  
Culture Models ◽  
Genome Activation

Targeted protein degradation methods offer a unique avenue to assess a protein's function in a variety of model systems. Recently, these approaches have been applied to mammalian cell culture models, enabling unprecedented temporal control of protein function. However, the efficacy of these systems at the tissue and organismal levels in vivo is not well established. Here, we tested the functionality of the degradation tag (dTAG) degron system in mammalian development. We generated a homozygous knock-in mouse with a FKBPF36V tag fused to Negative elongation factor b (Nelfb) locus, a ubiquitously expressed protein regulator of transcription. In the first validation of targeted endogenous protein degradation across mammalian development, we demonstrate that irrespective of the route of administration the dTAG system is safe, rapid, and efficient in embryos from the zygote to midgestation stages. Additionally, acute early depletion of NELFB revealed a specific role in zygote-to-2-cell development and Zygotic Genome Activation (ZGA).

Kinetics of Peptide Hydrolase Activity in Crude Wheat Leaf Extracts

1987 ◽  
Vol 14 (4) ◽  
pp. 421
Author(s):  
R French ◽  
LG Paleg
Keyword(s):  
Protein Degradation ◽  
Kinetic Parameters ◽  
Leaf Extracts ◽  
Soluble Peptide ◽  
Endogenous Protein ◽  
Wheat Leaf ◽  
Intracellular Protein Degradation ◽  
Peptide Hydrolases ◽  
Kinetics Of

The protein present in crude wheat leaf extracts causes serious deviations from simple Michaelis-Menten kinetics for soluble peptide hydrolases. A theoretical analysis indicated that the usual approach, of adjusting activities observed at various substrate concentrations for the activity observed in the absence of added substrate, gave erroneous estimates of kinetic parameters. The size of the error depends on the concentration of endogenous protein and the Km for its degradation. A technique is suggested to allow an estimate to be made of the true values of the kinetic parameters. The method also allows estimation of the Km for the degradation of the endogenous protein. The Km for haemoglobin degradation by crude extracts of wheat primary leaves at pH 4.5 was 0.802 mg ml-1 and at pH 6.5 was 3.35 mg ml-1. The Km for endogenous protein degradation at pH 4.5 was 2.24 mg ml-1 and at pH 6.5 was 1.49 mg ml-1. The implications of these findings for the possible role of soluble peptide hydrolases in intracellular protein degradation is discussed.

scholarly journals The effect of starvation on branched-chain 2-oxo acid oxidation in rat muscle

1984 ◽  
Vol 219 (1) ◽  
pp. 253-260 ◽  
Author(s):  
A J M Wagenmakers ◽  
J H Veerkamp
Keyword(s):  
Amino Acid ◽  
Protein Degradation ◽  
Specific Radioactivity ◽  
Acid Oxidation ◽  
Oxidative Decarboxylation ◽  
Precursor Pool ◽  
Oxidation Rates ◽  
Branched Chain Amino Acid ◽  
Endogenous Protein ◽  
Branched Chain

Oxidative-decarboxylation rates of branched-chain amino acids in rat hemidiaphragm and of branched-chain 2-oxo acids in hemidiaphragm, soleus muscle and heart slices of 110-120 g rats were increased considerably by 3-4 days of starvation, when they were calculated from the specific radioactivity in the medium. When the supply from endogenous protein degradation to the oxidation-precursor pool was severely limited by transaminase inhibitors, oxidative-decarboxylation rates of branched-chain 2-oxo acids rose significantly. Since this apparent increase was relatively larger in preparations from fed rats than from 3-days-starved rats, the differences in oxidation rates with nutritional state became less or even not significant. With rat heart the smaller dilution of the oxidation precursor pool after starvation is in accordance with the reported decrease in protein breakdown. Since protein degradation increases with starvation in skeletal muscles, we suggest that the amino acid pool arising from protein degradation is more segregated from the oxidation precursor pool in muscles from starved than from fed rats. We conclude that starvation increases branched-chain amino acid and 2-oxo acid oxidation in skeletal and cardiac muscle considerably less than has been suggested by previous studies.

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