Protein industry, protease applications

Two other practical applications of enzyme technology used in dairy industry are the modification of proteins with proteases to reduce possible allergens in cow milk products fed to infants, and the hydrolysis of milk with lipases for the development of lipolytic flavors in speciality cheeses. 

High reaction rates at ambient temperatures and near neutral pH values are necessary to design artificial proteases applicable to food industries, catalytic turnover in the peptide hydrolysis, and hydrolysis of a broad range of protein substrates at selected sites. In addition, easy separation of the catalysts from protein hydrolysates is required. Construction of catalytic centers directly on immobile supports is, therefore, advantageous to designing artificial proteases applicable to protein industries. 

Proteases are used in many industrial areas as well as basic research. They are classified by their mechanism of catalysis. Proteases are used in the pharmacological, food and other consumer industries to convert raw materials into a final product or to alter properties of the raw material. In biomedical research, proteases are used to study the structure of other proteins and for nthesis of peptides. The choice of a protease for an application depends in part on its specificity for peptide bonds, activity and stability. Technical advances in protein engineering have enabled alteration of these properties and allowed proteases to be used more effectively. Some easily obtained proteases can be modified so that they can substitute for proteases whose supply is limited. 

Aehle, W., Sobek, H., Amory, A., Vetter, R., Wilke, D. Schomburg,D. (1993). Rational protein engineering and industrial application structure prediction by homology and rational design of protein-variants with improved washing performance the alkaline protease from Bacillus alcalophilus. Journal of Biotechnology, 28, 31-40. 

Semisynthesis has become a suitable technique for chemical variations of large polypeptides or proteins from natural sources. Human insulin differs from porcine insulin only in position B30, where alanine is the C-terminal B-chain residue of porcine insulin but threonine is the C-terminal of the human insulin B-chain. Among the various ways to obtain human insulin from porcine insulin by protease-catalyzed semisynthesis, the one-step conversion by exchange of the C-terminal alanine B of porcine insulin with a threonine residue seems to be the method of choice. Several proteases, e.g. trypsin, achromobacter protease, and car-boxypeptidase Y, are able to catalyze the conversion and various groups have independently described an essential improvement of the enzymatic semisynthesis of insulin.The Hoechst procedure,which was developed as an industrial process, is described below as an example of a large-scale conversion of porcine insulin to human insulin in kilogram amounts for therapeutic application. Based on this type of transamidation reaction, it is easy to prepare various B30-insulin analogues. 

Proteases are enzymes that break down protein molecules through peptide bond hydrolysis [1]. They are commercially employed in many industrial processes. In foods, proteases have two main applications in the processing of traditional food products and in the processing of new protein-based ingredients called functional foods [2]. Proteases are also used in other industrial segments such as leather industry, pharmaceutical, waste management, and the detergent industry. Currently, microbial proteases make up approximately 40% of total enzyme sales [3, 4]. 

Proteinaceous material such as horn, feather, nail, hair, and cheese whey occur in nature as waste and can be converted, by proteases, into liquid concentrates or dry solids with high protein content and of nutritional value for food and feed. Thus, proteases provide potential application for the management of residues from various food processing industries such as poultry and cattle slaughterhouses and fishing and dairy industries [5, 6],... 

Three other plant enzymes, papain, bromelain, and to a lesser extent ficin, have found acceptance in the food industry as proteases. Papain is derived from the latex of the fruit, leaves, and trunk of Carica papaya, and bromelain from the fruit and stems of pineapple plants. These enzymes are used to prevent the hazing of beer when chilled (Chill-Proofing) by modifying the protein. Other applications for these plant proteases are in meat tenderizers and digestive aids. Ficin from the latex of Ficus carica is used to a much lower extent, perhaps because of its marked action on native protein and difficult handling. Proteases from Aspergillus Jlavus-oryzae, and to a lesser extent from Bacillus subtilis, have been used to replace and supplement these plant proteases in all applications, but papain continues to have the widest acceptance. 

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