Proteolytic activity

FIGURE 15.4 The proteolytic activation of chymo trypsin ogen. 

Fig. 30. Chromatographic separation of 1) acid and 2) neutral proteases (Bac. Subtilis) on Biocarb-T biosorbent. A. proteolytic activity units/ml —o— B. protein concentration (E28o) — —...

Alzheimer s Disease. Figure 2 A(3 is derived from the APP by the sequential action of proteolytic activities exerted by (3- and y-secretases. APP-CTF is (C99) produced after cleavage of the APP by (3-secretase and represents the substrate of the y-secretase. The yellow box marks membrane embedded amino acid residues of A(3 peptide. Scissors represent the main cleavage sites of (3- and y-secretase, e.g. the e- and y-cleavages at positions 49,46, 42, 40 and 38. 

Apoptotic initiator caspases (caspase-2, -8, -9 and -10) constitute a subgroup of the caspase family. These caspases are the first to become proteolytically active in the apoptotic cascade. Their activation takes place in multiprotein complexes initiated by pro-apoptotic stimuli, such as TNFa, a-Fas, staurosporine. Once activated, they can process their substrates, which include the apoptotic executioner caspases. 

Endothelin Concerting Enzymes (ECEs) belong to the family of metalloproteases that catalyze the proteolytic activation of big endothelins. 

MMPS Gelatinase-B, 92 kDa gelatinase Secreted MM P-9 plays a regulatory role in angiogenesis not only through proteolytic activity but also through other downstream angiogenic factors... 

An enzyme in which the single catalytic residue is at the N-terminus of the protein. Many Ntn-hydrolases are synthesized as precursors and autoactivate the precursors are therefore peptidases, even if the mature enzyme has no further proteolytic activity. Three of the beta subunits of the proteasome are Ntn-hydrolases. 

Proteases are hydrolytic enzymes with important application in industries, in particular, in detergent and in the food industry. A metagenomic study in which 100 000 plasmid clones were screened for proteolytic activity found one positive done, which was determined to be novel by sequencing analysis [84]. 

Delivery of peptides and proteins via the gastrointestinal tract has not been successful because of poor penetration through the intestinal epithelium and high levels of proteolytic activity in the gastrointestinal tract. Liposomal encapsulation of proteins and peptides will not improve the efficiency and capacity of this absorption pathway considerably (e.g., Ryman et al., 1982 Machy and Leserman, 1987 Weiner and Chia-Ming Chiang, 1988). These difficulties in delivery via the oral route caused the parenteral route to remain the preferred route for the administration of therapeutic peptides... 

Figure 51-7. Scheme of sites of action of streptokinase, tissue plasminogen activator (t-PA), urokinase, plasminogen activator inhibitor, and Kj-antiplasmin (the last two proteins exert inhibitory actions). Streptokinase forms a complex with plasminogen, which exhibits proteolytic activity this cleaves some plasminogen to plasmin, initiating fibrinolysis. 

Proudfoot AE, Buser R, Borlat F et al (1999) Amino-terminally modified RANTES analogues demonstrate differential effects on RANTES receptors. J Biol Chem 274 32478-32485 Qin AP, Zhang HE, Qin ZH (2008) Mechanisms of lysosomal proteases participating in cerebral ischemia-induced neuronal death. Neurosci Bull 24 117-123 Richter R, Bistrian R, Escher S et al (2005) Quantum proteolytic activation of chemokine CCL15 by neutrophil granulocytes modulates mononuclear cell adhesiveness. J Immunol 175 1599-1608... 

Complement is not a single protein but comprises a group of functionally linked proteins that interact with each other to provide mar of the effector functions of humoral immunity and inflammation. Most of the components of the system are present in the serum as proenzymes, i.e. enzyme precursors. Activation of a complement molecule occurs as a result of proteolytic cleavage of the molecule, which in itself confers proteolytic activity on the molecule. Thus, many components of the system serve as the substrate of a prior component and, in turn, activate a subsequent component. This pattern of sequential activation results in the system being called the complement cascade. ... 

A recent report has demonstrated that the proteolytic activity of NS3 plays an additional role in viral infection, beyond polyprotein processing. An important mediator of the cellular immune response is the transcription factor interferon regulatory factor 3 (IRF-3), which becomes activated on infection and then stimulates production of type-1 interferon and other antiviral genes [46]. It was found that expression of heterodimeric NS3/4A... 

Radlowski, M., Kalinowski, A., Adamczyk, J., Krolikowski, Z. and Bartkowiak, S. (1996). Proteolytic activity in the maize pollen wall.Physiologia Plantarum 98 172-178. 

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