Proteinases applications

Inhibitors of Serine Proteinase -Application in Agriculture and Medicine... 

Casein may be coagulated and recovered as rennet casein by treatment of milk with selected proteinases (rennets). However, one of the caseins, K-casein, is hydrolysed during renneting and therefore the properties of rennet casein differ fundamentally from those of acid casein. Rennet casein, which contains the colloidal calcium phosphate of milk, is insoluble in water at pH 7 but can be dissolved by adding calcium sequestering agents, usually citrates or polyphosphates. It has desirable functional properties for certain food applications, e.g. in the production of cheese analogues. 

Since the principal constituents of milk are proteins, lipids and lactose, proteinases, lipases and / -galactosidase (lactase) are the principal exogenous enzymes used in dairy technology. Apart from these, there are, at present, only minor applications for glucose oxidase, catalase, superoxide dismutase and lysozyme. Lactoperoxidase, xanthine oxidase and sulphydryl oxidase might also be included, although at present the indigenous form of these enzymes is exploited. 

There is one major (rennet) and several minor applications of proteinases in dairy technology. 

Rennets. The use of rennets in cheesemaking is the principal application of proteinases in food processing and is second only to amylases among industrial applications of enzymes. The sources of rennets and their role in milk coagulation and cheese ripening are discussed in Chapter 10 and will not be considered here. 

A novel, potentially very significant, application of proteinases in milk protein technology is the production of biologically active peptides (Chapter 4). Carefully selected proteinases of known specificity are required for such applications, but the resulting products have high added value. 

J.O. Capobianco, C.G. Lerner, and R.C. Goldman, Application of a fluorogenic substrate in the assay of proteolytic activity and in the discovery of a potent inhibitor of Candida albicans aspartic proteinase, Anal. Biochem., 204, 96, 1992. 

Coumarins, too, fluoresce, notably when an electron-releasing group is present at the 7-position. For example, A-acyl derivatives of some 7-aminocoumarins serve as fluorescent markers for the detection of proteinases (80MI22403). Coumarins show a propensity to absorb UV light and this results in a number of applications. A particularly simple illustration is the use of umbelliferone, 7-hydroxycoumarin, in sun-screen lotions. 

Akpinar, O. 1998. Characterization of recombinant proteinase inhibitors in surimi application. M.S. thesis. Oregon State University, Corvallis. 

Nagano, I., Pei, F., Wu, Z., Wu, J., Cui, H., Boonmars, T. and Takahashi, Y. (2004) Molecular expression of a cysteine proteinase of Clonorchis sinensis and its application to an enzyme-linked immunosorbent assay for immunodiagnosis of clonorchiasis. Clinical, Diagnostic and Laboratory Immunology 11, 411 f16. 

Nilges, M., Gronenborn, A. M., Brunger, A. T. and Clore, G M. (1988). Determination of three-dimensional structures of proteins by simulated annealing with interproton distance restraints Application to crambin, potato carboxypeptidase inhibitor and barley serine proteinase inhibitor 2. Protein Eng. 2, 27-38. 

In eastern Europe. Letoozim , a mixture of the papaya proteinases, is used for the treatment of eye burns [115] as well as for some cases of cataract [1161. Recently, a new application for chymopapain has been reported, Chymodiactin has been used in the process of removal of tumor cells from autologous marrow grafts in a positive selection system [117,118], This process clears the way for the use of autologous bone marrow transplants in the treatment of several types of cancer, since the authors showed tlst hemopoietic stem cells, the nrecyr ors of al lymphohemopoietic lineages, are present in cell mixtures purified in this way [119],... 

Application of ALPH to serine proteinases as an axiom thus results in a requirement for a separate kinetic event, nitrogen inversion. In the absence of additional evidence for such an event, therefore, serine proteinase action would be accounted an area in which ALPH probably fails, but two negative results provide some evidence that the tetrahedral intermediate is indeed first formed in conformation [102b]. Bizzozero and Zweifel (1975) found that amides [104] and [105] were not detectably hydrolysed by chymotrypsin,... 

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