Degradation of Proteins

Infusion Method. Infusion is a classic method for top-fermented beers and is used for ad British types. The whole mash is heated graduady from mashing-in to mashing-off with holding times for the degradation of protein and starch. No part of the mash is boiled and the malt, therefore, must be well-modified to assure the breakdown of ad soluble substances. Because no boiling takes place there is no physical breakdown of the malt, and consequentiy infusion is not as effective as decoction despite the better protection of the enzymes. 

As a result of the en2ymatic degradation of proteins, key indexes change, ie, protein solubiUty indexes (PSI), peptide chain length (PCL), and protein solubihty in 0.8 Af TCA (TCA-index) (Fig. 14). Unpleasant bitterness was once a problem for some protein hydroly2ates. This problem can now be overcome by proper selection of the reaction parameters and the en2ymes used. 

Multiprotein complex that catalyses ATP-dependent degradation of proteins tagged with ubiquitin. 

Sakaida, S., Kyle, M. and Farber, J.L. (1990). Autophagic degradation of protein generates a pool of ferric iron required for the killing of cultured hepatocytes by an oxidative stress. Mol. Pharmacol. 37, 435-442. 

The degradation of proteins in the solid state occur to a lesser extent and typically via different mechanisms than those that occur in solution [109,110]. Lyophilization is currently the more common technique in the manufacture of dried therapeutic proteins however, there is increasing interest in the use of spraydrying, owing to the unique physical nature of the spray-dried powder and its potential usefulness in protein drug delivery. 

A PFR has been designed in which steam is injected into the whey as it enters the reactor. After it passes through the PFR, the temperature is dropped rapidly to 10 °C, where the rate of degradation is negligible. A holding time of 7 sec is needed to obtain 99.99% spore kill at a temperature of 127 CC. For the whey to meet health and flavor tests, a maximum of 10% degradation of protein is to be allowed. As a first approximation in your analysis, the reaction is to be treated as isothermal at 127 °C. 

Steward, O. and Schuman, E. M. Compartmentalized synthesis and degradation of proteins in neurons. Neuron 40 347-359, 2003. 

Fietzek, P. P., and Kiihn, K. Automation of the Sequence Analysis by Edman Degradation of Proteins and Peptides. 29, 1-28 (1972). 

Aminoacyl-tRNA synthetases Degradation of proteins, peptides, and glycopeptides Nucleoproteins Protein modification... 

K. Patel, R. T. Borchardt, Deamidation of Asparaginyl Residues in Proteins A Potential Pathway for Chemical Degradation of Proteins in Lyophihzed Dosage Form , J. Parent. Sci. Technol. 1990,44, 300-301. 

Three other components that my laboratory has identified and partially purified from Fraction 2 of reticulocytes, termed CF1-CF3, are involved in the degradation of proteins ligated to ubiquitin [24]. These are apparently subcomplexes of the 26S proteasome, a large ATP-dependent protease complex first described by Re-chsteiner and co-workers [25], CF3 is identical to the 20S proteasome core particle [26], while CFl and CF2 may be similar to the base and lid subcomplexes of the 19S regulatory particle of the 26S proteasome, described more recently by the Finley laboratory [27], In hindsight, the reason for finding subcomplexes, rather than the complete 26S complex in Fraction 2 was technical we have routinely prepared Fraction 2 from ATP-depleted reticulocytes [20], under which conditions the 26S proteasome dissociates to its subcomplexes. We found that incubation of the three subcomplexes in the presence of ATP promotes their assembly to the 26S proteasome [24, 26]. The role of ATP in the assembly of the 26S proteasome complex remains unknown. 

However, it is still possible that other mechanisms may exist to bridge the gap between substrate and E2 in the SCF-mediated ubiquitin-transfer reaction. For example, reports suggest that SCF may form higher order structures to facilitate the degradation of protein substrates. The S. pombe F-box proteins Popl and Pop2 have been shown to form heterodimers, and evidence suggests that these interactions may be important for the degradation of their in vivo substrates [62]. 

Akopian, T. N., Kisselev, A. F., and Goldberg, A. L. Processive degradation of proteins and other catatlytic properties of the proteasome from Thermoplasma acidophilum. J. Biol. 

In that sense peptides represent a paramount example of how Nature diversifies from one single gene to generate multiple sets of biomolecules resulting from degradation of proteins by a complex network of proteases present in a living cell. 

Recent Developments in Chemical Modification and Sequential Degradation of Proteins George R. Stark... 

In addition to the intrinsic subunits, proteins that interact with the proteasome complex regulate its activity/ Often the cofactors are components of the ubiquitin pathway. Proteins such as chaperones and heat-shock proteins also assist in proteasome-mediated degradation of proteins. 

Protein represents the second largest store of chemical energy in the body, but it is not used for generating ATP except in some diseases and in some extreme conditions (e.g. prolonged starvation, very sustained exercise). The largest deposit of protein in the body is in skeletal muscle (about 40% of body weight). The synthesis of proteins requires amino acids whereas degradation of proteins pro-... 

Some key intracellular processes, which involve degradation of protein, utilise this system ... 

Once all the fat has been nsed, the rate of degradation of protein, now the only fnel, mnst increase considerably. The exact canse of death in snch circnmstances is not always clear a stndy of starvation in the Western Netherlands in 1944 5 (see Box 16.1) raised a number of possibilities ... 

One obvious symptom of a patient suffering from trauma is loss of body weight. This is due to increased mobilisation of both triacylglycerol in adipose tissue and degradation of protein in skeletal muscle. 

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