Proteins degradable

The thermodynamic stability of a protein in its native state is small and depends on the differences in entropy and enthalpy between the native state and the unfolded state. From the biological point of view it is important that this free energy difference is small because cells must be able to degrade proteins as well as synthesize them, and the functions of many proteins require structural flexibility. 

Cathepsins are intracellular proteinases that reside within lysosomes or specific intracellular granules. Cathepsins are used to degrade proteins or pqffides that are internalised from the extracellular space. Some cathepsins such as cathepsin-G or cathepsin-K may be released from the cell to degrade specific extracellular matrix proteins. All cathepsins except cathepsin-G (serine) and cathepsin-D (aspartyl) are cysteine proteinases. 

In eukaryotes, anabolic and catabolic pathways that interconvert common products may take place in specific subcellular compartments. For example, many of the enzymes that degrade proteins and polysaccharides reside inside organelles called lysosomes. Similarly, fatty acid biosynthesis occurs in the cytosol, whereas fatty... 

PROTEASES PEPTIDASES DEGRADE PROTEINS TO AMINO ACIDS... 

T cells all have the ahility to internalize and degrade proteins into peptide fragments and ean all therefore aet as APCs. 

Permonosulphuric acid treatment confers only a modest shrink-resist effect which usually needs to be improved by a subsequent additive treatment. It has been suggested [300] that the most likely mechanism for inhibiting felting by permonosulphuric acid treatment is the removal of degraded protein from below the exocuticle, producing a modified surface with a reduced differential friction. The direct formation from cystine residues of low concentrations of Bunte salts has been confirmed, as indicated in Scheme 10.42. 

Boisvenue, R.J., Stiff, M.I., Tonkinson, L.V., Cox, G.N. and Hageman, R. (1992) Fibrinogen-degrading proteins from Haemonchus contortus used to vaccinate sheep. American Journal of Veterinary Research 53, 1263-1265. 

Murthy N, Xu M, Schuck S et al (2003) A macromolecular delivery vehicle for protein-based vaccines Acid-degradable protein-loaded microgels. Proc Natl Acad Sci USA 29 4995-5000... 

The alanine cycle accomplishes the same thing as the Cori cycle, except with an add-on feature (Fig. 17-11). Under conditions under which muscle is degrading protein (fasting, starvation, exhaustion), muscle must get rid of excess carbon waste (lactate and pyruvate) but also nitrogen waste from the metabolism of amino acids. Muscle (and other tissues) removes amino groups from amino acids by transamination with a 2-keto acid such as pyruvate (oxaloacetate is the other common 2-keto acid). 

The proteolytic activity of some multicatalytic peptidases is stimulated by ATP, whereas that of others is not influenced by ATP [32], The ATP-dependent proteolytic system first found in reticulocytes requires the presence of a heat-stable polypeptide called ubiquitin, one of the roles of which is to mark particular proteins for subsequent degradation [33. ATP-Indepen-dent multicatalytic peptidases can degrade proteins that have a free amino or an /V-acctylatcd terminus, as well as oxidatively altered or phosphorylat-ed proteins [34], The small peptides generated are resistant to multicatalytic peptidases and are further degraded by cytoplasmic endopeptidases and exopeptidases. 

FIoskins, j. R., Yanagihara, K., Mizuuchi, K., and Wickner, S. ClpAP and ClpXP degrade proteins with tags located in the interior of the primary sequence. Proc Natl Acad Sd USA 2002, 99, 11037-42. 

Degrades glycogen and burns fat Bums fat and ketone bodies and degrades proteins Bums fat and ketone bodies and degrades proteins... 

The initial crystals of NPl were obtained with protein painstakingly isolated from Rhodnius salivary glands by the Ribeiro laboratory (44). This group also cloned all four nitrophorins (44, 45), which unfortunately resulted only in inclusion bodies or degraded protein in various... 

Wickner, S., M. R. Maurizi, and S. Gottesman. Posttranslational quality control folding, refolding, and degrading proteins. Science. 286 1888-1893.1999. 

Rogers, S., Wells, R., and Rechsteiner, M. (1986) Amino acid sequences common to rapidly degraded proteins The PEST hypothesis Science 234, 364-368. 

The cyclosome (or APC) is a high molecular weight complex that degrades proteins containing a specific recognition sequence, the destruction box (see chapter 13.2.4). Substrates are cell cycle regulators as e.g. cyclins, kinase inhibitors and spindle-associated proteins. Importantly, some forms of the cyclosome require phosphorylation in order to be active (fig. 2.15B). It is still unclear which of the many subunits carries the E3 enzyme activity. 

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