Protease bacterial

Cured hides must be properly soaked to obtain satisfactory rehydration and removal of unwanted material. InterfibnUar proteins should be degraded in order to increase water uptake. Bacterial proteases and pancreatic proteases are normally preferred, and are compatible with most tannery chemicals used in soaking, ie, most surfactants and preservatives containing sodium chlorite. 

If the yeast does not get enough free amino nitrogen, the fermentation will be poor and the beer quaHty inferior. A neutral bacterial protease added at mashing-in can be used to raise the level of free amino nitrogen. This is useful when working with poorly modified malt or with high adjunct ratios. 

Bacterial protease B. subtilis Desizing fibres, spot remover... 

The serine proteases are the most extensively studied class of enzymes. These enzymes are characterized by the presence of a unique serine amino acid. Two major evolutionary families are presented in this class. The bacterial protease subtilisin and the trypsin family, which includes the enzymes trypsin, chymotrypsin, elastase as well as thrombin, plasmin, and others involved in a diverse range of cellular functions including digestion, blood clotting, hormone production, and complement activation. The trypsin family catalyzes the reaction ... 

Azghani, A.O., Gray, L.D. and Johnson, AR. (1993) A bacterial protease perturbs the paracellular barrier function of transporting epithelial cell monolayers in culture. Infection and Immunity 61, 2681-2686. 

Soya Proteins. Early attempts to make albumen substitutes from soya protein also ran into problems. A bean flavour tended to appear in the finished product. A solution to these problems has been found. Whipping agents based on enzyme modified soy proteins are now available. The advantage of enzymatic modification is that by appropriate choice of enzymes the protein can be modified in a very controlled way. Chemical treatment would be far less specific. In making these materials the manufacturer has control of the substrate and the enzyme, allowing the final product to be almost made to order. The substrates used are oil-free soy flakes or flour or soy protein concentrate or isolate. The enzymes to use are chosen from a combination of pepsin, papain, ficin, trypsin or bacterial proteases. The substrate will be treated with one or more enzymes under carefully controlled conditions. The finished product is then spray dried. 

Although extensive biochemical data on both the bacterial and eukaryotic ATP-dependent proteases are available, the characterization of these proteolytic machines at atomic resolution has proven difficult, because of both the large size of these complexes and their lability to proteolysis and dissociation. No structural data at all are currently available for Lon and the mitochondrial ATP-dependent proteases. In the case of the cytosolic, membrane-integrated bacterial protease FtsH, atomic resolution data are available only for the ATPase domain (Krzywda et al. 2002 Niwa et al. 2002). In contrast, the ATP-dependent activators of the ClpAP and ClpXP proteolytic machines have so far resisted crystallization. Atomic resolution data are available only for the proteolytic component ClpP (Wang et al. 1997), and separately for a ClpX monomer (Kim and Kim 2003) and a ClpA monomer (Guo et al. 2002b). 

The bacterial protease HslVU is unique in two respects at present, it is the only ATP-dependent protease to have atomic coordinates of the full complex determined secondly, and in contrast to all other bacterial ATP-dependent proteases, it contains a proteolytic core that is related to the 20S proteolytic core of archaebacterial and eukaryotic proteasomes. The following sections summarize our understanding of HslVU biochemistry, crystallography, and enzymology and end with some speculation on the implications of these results for other ATP-dependent proteases. 

A practical enzymatic procedure using alcalase as biocatalyst has been developed for the synthesis of hydrophilic peptides.Alcalase is an industrial alkaline protease from Bacillus licheniformis produced by Novozymes that has been used as a detergent and for silk degumming. The major enzyme component of alcalase is the serine protease subtilisin Carlsberg, which is one of the fully characterized bacterial proteases. Alcalase has better stability and activity in polar organic solvents, such as alcohols, acetonitrile, dimethylformamide, etc., than other proteases. In addition, alcalase has wide specificity and both l- and o-amino acids that are accepted as nucleophiles at the p-1 subsite. Therefore, alcalase is a suitable biocatalyst to catalyse peptide bond formation in organic solvents under kinetic control without any racemization of the amino acids (Scheme 5.1). 

Based on the results in Chapter 2, one might speculate that inhibition of bacterial proteases promotes caries arrestment. Patent literature mentions both the application and inhibition of proteases for caries arrestment. Proteases may serve either the lysis of bacteria or the removal of infected dentin prior to restoration placement. 

The gross proteolysis of casein is probably due solely to rennet and plasmin activity (O Keeffe et al. 1978). Bacterial proteases and peptides are responsible for subsequent breakdown of the large peptides produced by rennet and plasmin into successively smaller peptides and finally amino acids (O Keeffe et al. 1978). If the relative rate of proteinase activity by rennet, plasmin, and bacterial proteases exceeds that of the bacterial peptidase system, bitterness in the cheese could result. Bitter peptides can be produced from a,-,- or /3-casein by the action of rennet or the activity of bacterial proteinase on /3-casein (Visser et al. 1983). The proteolytic breakdown of /3-casein and the subsequent development of bitterness are strongly retarded by the presence of salt (Fox and Walley 1971 Stadhouders et al. 1983). The principal source of bitter peptides in Gouda cheese is 3-casein, and more particularly the C-terminal region, i.e., 3(193-209) and 3(193-207) (Visser et al. 1983). In model systems, bitter peptides are completely debittered by a peptidases system of S. cremoris (Visser et al. 1983). 

Solution B Make up fresh and store on ice. Dissolve 65 casein units of bacterial protease in 10 ml water. Store on ice. 

The serine proteases are divided into at least two genetic families the mammalian serine proteases, such as trypsin, chymotrypsin, elastase, the enzymes of the blood clotting system, and many other proteases with specific roles in control of systems and the bacterial proteases called subtilisins (first to be isolated from Bacillus amyloliquefaciens), which are genetically unrelated to the mammalian enzymes but independently evolved the same mechanism (evolutionary convergence). 

Harvest cells by centrifuging at 5000for 15 min at 4 °C. Remove the supernatant and resuspend the cell pellet in 50 ml oflysis buffer + 500 p of bacterial protease inhibitor cocktail (Sigma). At this point, the cells can be frozen and stored at — 80 °C. 

Sample Preparation Using Tris Buffer, prepare a solution of the sample enzyme preparation so that 2 mL of the final dilution will contain between 10 and 44 bacterial protease units. 

Calculation One bacterial protease unit (PC) is defined as that quantity of enzyme that produces the equivalent of 1.5 pig/mL of L-tyrosine per min under the conditions of the assay. 

The cells are lysed on the filter at pH 9.6 at room temperature in the solution containing 0.05 M Tris, 0.05 M glycine, 0.025 M Na2-EDTA, 2% (w/v) sodium dodecyl sulphate containing 0.5 mg/ml freshly dissolved proteinase K (Boehringer, Ltd.). This is a broad specificity bacterial protease which will work in SDS. 

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