Proline endopeptidase

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

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-... 

Gibson, A. M., Edwardson, J. A., McDermott, J. R. Post mortem levels of some brain peptidases in Alzheimer s disease reduction in proline endopeptidase activity in cerebral cortex. Neurosci. Res. Commun. 1991,9 73-81. 

Mantle, D., Falkous, G., Ishiura, S., Blanchard, P. J., Perry, E. K. Comparison of proline endopeptidase activity in brain tissue from normal cases and cases with Alzheimer s disease, Lewy body dementia, Parkinson s disease and Huntington s disease. Clin. Chim. Acta 1996, 249 129-139. 

Proline endopeptidase (EC 3.4.-24.26 post-proline endopeptidase TRH deamidating enzyme) is a soluble serine protease. Notable substrates include angiotensin I, angiotensin II, bradykinin. LH-RH, neurotensin and substance P. Inhibitors include Cbz-Pro-Prolinal. 

Peptidases. Others members of the serine protease family, cleave oligopeptides and do not necessarily act on proteins. These include two peptidases of particular interest (dipeptidylpeptidase IV and proline endopeptidase). See also AMINOPEPTIDASE INHIBITORS CARBOXYPEPTIDASE INHIBITORS ... 

The same enzymes that are found in the liver are present in small amounts in mucosal cells. They catalyze oxidations, reductions, hydrolysis, and conjugations. Specific activities of the enzymes are lower than in the liver, but the activity can increase by induction. For many drug molecules, the concentration is higher than in the liver, so there is a higher number of reaction cycles per time unit and per mole of enzyme. Proline endopeptidases cleave the Pro-NKb bond in proteins and peptides [22]. 

Camargo, A.C. Caldo, H. Emson, P.C. (1983). Degradation of neurotensin by rabbit brain endo-oligopeptidase A and endo-oligopeptidase B (proline-endopeptidase). Biochemical and Biophysical Research Communications, Vol. 116(3), pp. 1151-1159. 

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... 

The starter cells begin to die off at the end of curd manufacture (Figure 10.21) the dead cells may lyse and release their intracellular endopeptidases (Pep O, Pep F), aminopeptidases (including Pep N, Pep A, Pep C, Pep X), tripeptidases and dipeptidases (including proline-specific peptidases) which produce a range of free amino acids (Figure 10.22). About 150 peptides have... 

J.-B. Charbonnier and A. M nez, Engineering cyclophilin into a proline -specific endopeptidase, Science 1998, 391, 301-304. 

Although any of several combinations of proteases can be used, ideally, one or more non-specific endopeptidases should be used first to convert the protein into many small peptides. These small peptides can then be degraded to amino acids by aminopeptidases and prolidase (hydrolyzes X-Pro bonds). Sometimes, carboxypeptidases are also used. Although leucine aminopeptidase has been used as the amino-peptidase (see Hill and Schmidt 1962), it may be preferable to use aminopeptidase M (Rohm and Haas, supplied by Henley and Co. of N.Y.), since this enzyme removes most residues at acceptable rates. Leucine aminopeptidase removes hydrophobic residues most rapidly, whereas some other residues are removed very slowly. Most procedures should probably include the use of prolidase (Miles) since many aminopeptidases do not cleave X-Pro bonds at appreciable rates. If it is found that proline is not released quantitatively by these procedures, the use of citrus leaf carboxypeptidase C (Rohm and Haas) can be tried after the initial endopeptidase hydrolysis and before the addition of aminopeptidase M and prolidase. Carboxypeptidase C (also yeast carboxypeptidase Y - see Hayashi et al. 1973) hydrolyzes proline bonds (as well as all others), but if proline is at or adjacent to the NH2 terminus of a peptide, it would probably not be released. In all procedures a control consisting of the enzymes only should be run in parallel with the hydrolyzed sample, and corrections should be made for any amino acids found by analysis of the control. suhic / /< > , mi... 

All human metalloendoproteinases are metzincins, named for a downstream methionine residue involved in regulating catalysis by mediating a critical turn that brings an adjacent tyrosine or proline residue close to the catalytic zinc ion. Matrilysins (also called matrix metalloendoproteinases, MMPs) are the major class of metzincin endopeptidases involved in collagen and stromal degradation. The other two classes, adantalysins and... 

Protease, Proline-Specific Endopeptidase Origin Flavobacterium sp. Toyobo... 

McMahon, G., Collins, P. and O Connor, B. (2003) Characterisation of the active site of a newly-discovered and potentially significant post-proline cleaving endopeptidase called ZIP using LC-UV-MS. Analyst, 128 (6), 670-5. 

None of the exopeptidases or endopeptidases that we have mentioned will catalyze the hydrolysis of an amide bond if proline is at the hydrolysis site. These enzymes recognize the appropriate hydrolysis site by its shape and charge, and proline s structure causes the hydrolysis site to have an unrecognizable three-dimensional shape. 

Cyanogen bromide (BrC=N) causes the hydrolysis of the amide bond on the C-side of a methionine residue. Cyanogen bromide is more specific than the endopeptidases about what peptide bonds it cleaves, so it provides more reliable information about the primary structure (the sequence of amino acids). Because cyanogen bromide is not a protein and therefore does not recognize the substrate by its shape, cyanogen bromide will still cleave the peptide bond if proline is at the cleavage site. 

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