Proteases endopeptidase

Proteases (endopeptidases or proteinases) commonly used for specific cleavage of proteins are summarised in Table 6.2. Trypsin is almost always used as an enzyme of first choice it is highly specific and stable, has an appropriate pH-optimum and is commercially available in high purity and quality. When the results obtained are ambiguous, or the trypsin cannot be used for any other reason, a different protease can be easily chosen. In all experiments, described here, the trypsin cleavage was applied. 

Protease, Endopeptidase Origin Bacillus licheniformis Novozymes Alcalase ... 

ET-1 from big-ET-1 by other proteases such as neutral endopeptidase or other currently unidentified proteases. Therefore, dual inhibition of ECE and NEP might inhibit ET-l generation more efficiently, than that seen for selective ECE inhibitors. However, dual inhibiton of ECE and NEP could also increase the risk for the development of AD, as both enzyme classes are involved in the degradation of A 3 peptide. 

Fibrinolytic effecting protease enzyme from the poison secretion (venom) of Bothrops atrox with glycoprotein structure. It has thrombin similarly endopeptidase activity. 

There are two main classes of proteolytic digestive enzymes (proteases), with different specificities for the amino acids forming the peptide bond to be hydrolyzed. Endopeptidases hydrolyze peptide bonds between specific amino acids throughout the molecule. They are the first enzymes to act, yielding a larger number of smaller fragments, eg, pepsin in the gastric juice and trypsin, chymotrypsin, and elastase secreted into the small intestine by the pancreas. Exopeptidases catalyze the hydrolysis of peptide bonds, one at a time, fi"om the ends of polypeptides. Carboxypeptidases, secreted in the pancreatic juice, release amino acids from rhe free carboxyl terminal, and aminopeptidases, secreted by the intestinal mucosal cells, release amino acids from the amino terminal. Dipeptides, which are not substrates for exopeptidases, are hydrolyzed in the brush border of intestinal mucosal cells by dipeptidases. 

Cysteinyl proteases Cathepsins (B, H, K, M, S, T) Proline endopeptidase Interleukin-converting enzyme Apopain (CPP-32)... 

Proteases, which can be classified as either peptidases or proteinases. These cleave polypeptide chains eventually into their component amino acids. Peptidases can be further classified as endopeptidases (which act on the main-chain amido groups along the polypeptide molecule) or as exopeptidases (which act only at terminal amino acid residues). 

The NC-IUBMB has introduced a number of changes in the terminology following the proposals made by Barrett, Rawlings and co-workers [7] [8]. The term peptidase should now be used as a synonym for peptide hydrolase and includes all enzymes that hydrolyze peptide bonds. Previously the term peptidases was restricted to exopeptidases . The terms peptidase and protease are now synonymous. For consistency with this nomenclature, the term proteinases has been replaced by endopeptidases . To complete this note on terminology, we remind the reader that the terms cysteine endopeptidases and aspartic endopeptidases were previously called thiol proteinases and acid or carboxyl proteinases , respectively [9],... 

A novel concept of using bioadhesive polymers as enzyme inhibitors has been developed [97]. Included are derivatives of poly acrylic acid, polycarbophil, and car-bomer to protect therapeutically important proteins and peptides from proteolytic activity of enzymes, endopeptidases (trypsin and a-chymotrypsin), exopeptidases (carboxypeptidases A and B), and microsomal and cytosolic leucine aminopeptidase. However, cysteine protease (pyroglutamyl aminopeptidase) is not inhibited by polycarbophil and carbomer [97]. 

In addition, renal tubular cells contain various proteases for the degradation of proteins and oligopeptides. These enzymes are located predominantly in the lysosomes and micro-somes of these cells, but some have been reported on the brush-border membranes [16]. Degradative enzymes include various endopeptidases, exopeptidases and esterases [17]. 

Prolyl endopeptidase (PEP, EC 3.4.21.26) is the only serine protease which is known to cleave a peptide substrate in the C terminal side of a proline residue... 

This enzyme [EC 3.4.21.39], also referred to as mast cell protease I and skeletal muscle (SK) protease, is an endopeptidase that has been isolated from mast cell granules. It belongs to the peptidase family SI and catalyzes the hydrolysis of peptide bonds, preferring Phe-Xaa > Tyr-Xaa > Trp-Xaa > Leu-Xaa. 

Glutamyl endopeptidase [EC 3.4.21.19] (also known as staphylococcal serine proteinase, V8 proteinase, protease V8, and endoproteinase Glu-C), a member of the peptidase family S2B, catalyzes the hydrolysis of Asp-Xaa and Glu-Xaa peptide bonds. In appropriate buffers, the specificity of the bond cleavage is restricted to Glu-Xaa. Peptide bonds involving bulky side chains of hydrophobic aminoacyl residues are hydrolyzed at a lower rate. 

Glutamyl endopeptidase 11 [EC 3.4.21.82], also known as glutamic acid-specific protease, catalyzes the hydrolysis of peptide bonds, exhibiting a preference for Glu-Xaa bonds much more than for Asp-Xaa bonds. The enzyme has a preference for prolyl or leucyl residues at P2 and phenylalanyl at P3. Hydrolysis of Glu-Pro and Asp-Pro bonds is slow. This endopeptidase is a member of the peptidase family S2A. 

Proteolysis of peptides and proteins by enzymes occurs in a selective or nonselective manner. Chymotrypsin, trypsin, lysyl endopeptidase, Staphylococcus aureus V8 protease, and en-dopeptidase Asp-N are frequently listed as selective enzymes, whereas thermolysin, pepsin, subtilisin, and elastase belong to the nonselective enzymes, although thermolysin preferentially cleaves peptide bonds before hydrophobic residues. 

Disulfide Connectivities of a GM2 Activator Protein Fragment (24) Prepared by Digestion with Trypsin, S. aureus V8 Protease and Endopeptidase Asp-N [79 ... 

Several different proteases can attack a single protein at enzyme-selective amino-acid sequences. Proteases can be divided into two categories. Endopeptidases are enzymes that cleave peptide bonds between specific, nonterminal amino acids. There are endopeptidases specific for just about every amino acid. Exopeptidases are enzymes that cleave terminal peptide bonds at either the C-terminus or N-terminus. 

Cystcinyi protease Papain CalhepsiL B Cathepsin-Pf Calhepsin-L Calhepsin-M Calhepsin-N Cathepsin-S Calhepsin-T Proiine endopeptidase Interleukin-converting enzyme... 

The cysteinyl proteases include papain calpains I and II cathepsins , H, and L proline endopeptidase and interleukin-converting enzyme (ICE) and its homologs. The most well-studied cysteinyl protease is likely papain, and the first x-ray crystallographic structures of papain [193] and a peptide chloromethylketone inhibitor-papain complex [194] provided the first high resolution molecular maps of the active site. Pioneering studies in the discovery of papain substrate peptide-based inhibitors having P, electrophilic moieties such as aldehydes [195], ketones (e.g., fluoromethylketone, which has been determined [196] to exhibit selectivity for cysteinyl proteases versus serinyl proteases), semicarbazones, and nitriles are noteworthy since 13C-NMR spectro-... 

The proteases may be conveniently classified according to their activities and functional groups. The serine proteases are endopeptidases that have a reactive... 

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