Proteinases cell-derived

Figure 10.23 Water-insoluble and water-soluble peptides derived from asl-casein (A), as2-casein (B) or -casein (C) isolated from Cheddar cheese DF = diafiltration. The principal chymosin, plasmin and lactococcal cell-envelope proteinase cleavage sites are indicated by arrows (data from T.K. Singh...

FIG. 14. Identity of peptides isolated from the water-soluble fraction of Cheddar cheese. Peptides derived from aji-casein are shown in A, those from /8-casein in B. The principal chymosin cleavage sites in Oji-casein, the principal plasmin cleavage sites in /8-casein, and the principal cleavage sites of lactococcal cell envelope proteinase on Oji- and -casein are shown by arrows (from Fox et al., 1994,1995, unpublished). 

Klagsbrun, M. et al.. Multiple forms of basic fibroblast growth factor amino-terminal cleavages by tumor cell- and brain cell-derived acid proteinases, Proc. Natl Acad. Sci. USA, 84, 1839, 1987. 

Dozens of different peptides have been identified in cheeses. Most of them arise from and -caseins and a few are from aj2-and K-caseins. The proteinases involved in hydrolysis of aj -casein are mainly cathepsin D originating from milk and cell-envelope proteinase from thermophilic starters, while P- and aj2-caseins are mainly hydrolysed by plasmin. Moreover, peptidases from starters are also active throughout the ripening process, presumably similar to those from non-starter lactic acid bacteria. For example, the bitterness of mature Gouda cheese is caused by calcium and magnesium chlorides, some bitter-tasting free amino acids and is modified by peptides, which arise from the hydrolysis of fS-casein (such as decapeptide Tyr-Pro-Phe-Pro-Gly-Pro-Ile-His-Asn-Ser and derived nonanpeptide without the terminal serine) and casein (tetrapeptide Leu-Pro-Gln-Glu). 

PPD Purified protein derivative PPME Polymeric polysaccharide rich in mannose-6-phosphate moieties PRA Percentage reactive activity PRD, PRDII Positive regulatory domain, -II PR3 Proteinase-3 PRBC Parasitized red blood cell proET-1 Proendothelin-1 PRL Prolactin PRP Platelet-rich plasma PS Phosphatidylserine P-selectin Platelet selectin formerly known as platelet adctivation-dependent granule external membrane protein (PADGEM), granule membrane protein of MW 140 kD (GMP-140)... 

As with UC, the immune activation seen in CD involves the release of many proinflammatory cytokines. Cytokines thought to play major roles in CD are derived from T-helper type 1 cells and include interferon-y, TNF-a, and IL-1, IL-6, and IL-12. TNF-a is a major contributor to the inflammatory process seen in CD. Its physiologic effects include activation of macrophages, procoagulant effects in the vascular endothelium, and increases in production of matrix metallo-proteinases in mucosal cells.9,15 Excessive production of both... 

The plasma proteinase, thrombin, a procoagulant enzyme with effects on platelets, endothelial cells and smooth muscle, has been shown to stimulate bone-marrow-derived murine mast cells to release histamine and jS-hexos-aminidase [135]. This secretory response is rapid, reaching a maximum in 1-2 min, and dose-dependent, beginning at about 0.1 U of thrombin and plateauing at 0.5 U thrombin. 

J. Molldrem, S. Dermime, K. Parker, Y.Z. Jiang, D. Mavroudis, N. Hensel, P. Fukushima, and A.J. Barrett, Targeted T-cell therapy for human leukemia c 4otoxic T lymphoc34es specific for a peptide derived from proteinase 3 preferentially lyse human myeloid leukemia cells, Blood88, 2450-2457 (1996). 

Although in vitro, the cell wall-associated proteinase of the Lactococcus starters is quite active on 8-casein (and that from some strains on asl-casein also), in cheese, they appear to act mainly on casein-derived peptides, produced by chymosin from asl-casein or by plasmin from / -casein. 

P2.m. The cysteine proteinases are one of four major classes of endoproteinases that possess the ability to degrade intact glomerular basement membranes [144]. All nucleated cells produce cystatin at a stable rate. More than 99% is freely filtered by the glomerulus with little secretion or reabsorption. As a result, it has many of the ideal features for use as a marker of kidney function and eshmate of GFR. Serum cystatin C concentrations demonstrate a good inverse correlation with radionuclide derived measurements of GFR and has been shown in several studies to be superior to creatinine and comparable to iohexol clearances in estimating eGFR [145,146]. 

---