Protease acidic

IV. Aspartic proteases (acid proteases) are rare in Bacteria and contain one or more aspartic acid residues in their active center. Inactivation of the enzyme can be achieved by alkylation of the aspartic acid residues with DAN (diazoacetyl-DL-norleucine methyl ester) 91 . 

In addition to the separation of coconut oil from a coconut milk emulsion, enzyme treatment can also be used to extract coconut oil from finely divided copra meal. Coconut oil extraction based on the enzymatic action of polygalacturonases, a-amylase and proteases on a diluted coconut paste has been tested (McGlone et al., 1986). After the reaction with enzymes, the mixture gave three phases upon centrifugation. The upper phase contained high quality coconut oil and the middle layer and the lower layer contained water and coconut meal respectively. This process gave a yield of 80%, which is a much higher yield compared to other traditional wet extraction methods. Enzyme assisted extractions have also been used to extract coconut oil from powdered copra. The crude commercial enzyme used in this study contained a-amylase, neutral protease, acid protease, cellulase/hemicellulase, and pectinase. The enzyme treatment in this process can be considered as a pretreatment of copra prior to the oil extraction. The enzyme was added 1% rate of the copra and allowed to stand for 30 min. After enzyme treatment, the meal was extracted by hot water and the emulsion was boiled to evaporate water. This enzyme pretreatment of copra prior to the extraction improved the yield of coconut oil by 50% compared to the same extraction procedure without enzyme... 

Extraction of hGH from pituitary glands has been accompHshed by a variety of procedures with or without protease inhibitors. One of the first commercial procedures used glacial acetic acid at 70°C to extract the hGH from the glands (39). 

The enzymatic hydrolysates of milk casein and soy protein sometimes have a strong bitter taste. The bitter taste is frequently developed by pepsin [9001 -75-6] chymotrypsin [9004-07-3] and some neutral proteases and accounted for by the existence of peptides that have a hydrophobic amino acid in the carboxyhc terminal (226). The relation between bitter taste and amino acid constitution has been discussed (227). 

Engineering Substrate Specificity. Although the serine proteases use a common catalytic mechanism, the enzymes have a wide variety of substrate specificities. For example, the natural variant subtiHsins of B. amyloliquefaciens (subtiHsin BPN J and B. licheniformis (subtiHsin Carlsberg) possess very similar stmctures and sequences where 86 of 275 amino acids are identical, but have different catalytic efficiencies, toward tetraamino acid -nitroanilide substrates (67). 

The function of Jisper Uis fermentation appears to be primarily the breakdown of protein and polysaccharides by secreted proteases and amylases. Replacement oiPispergillis by chemical or enzymatic hydrolysis has no major impact on the organoleptic properties of the sauce. Likewise, inoculation with a pure culture of Ixictobacillus delbrueckii to carry out the acetic acid fermentation produces a normal product. The S. rouxii and Toru/opsis yeasts, however, are specifically required for proper flavor development. 

Permeation enhancers are used to improve absorption through the gastric mucosa. Eor example, oral dehvery of insulin (mol wt = 6000) has been reported from a water-in-oH- emulsion containing lecithin, nonesterified fatty acids, cholesterol [57-88-5], and the protease inhibitor aprotinin [9087-70-1] (23). 

Co-buHders such as nitnlotriacetic acid or polycarboxylates also may be incorporated into the detergent formulation. Wash performance of detergents decreases with increasing calcium concentration. Protease performance varies, but high calcium concentrations tend to reduce protease performance. Therefore it is an advantage to add a buHder system to the detergent. Proteases need a smaH amount of calcium for the sake of stabHity, but even with the most efficient buHder systems, stabHity during wash is not a problem. 

Enzymes Degrading Macromolecules. Enzymes that degrade macromolecules such as membrane polysaccharides, stmctural and functional proteins, or nucleic acids, have all shown oncolytic activity. Treatment strategies include the treatment of inoperable tumors with pepsin (1) antitumor activity of carboxypeptidase (44) cytotoxicity of ribonudease (45—47) oncolytic activity of neuraminidase (48—52) therapy with neuraminidase of patients with acute myeloid leukemia (53) antitumor activity of proteases (54) and hyaluronidase treatment in the management of human soHd tumors (55). 

An example of a pseudoirreversible inhibitor has been demonstrated for chymotrypsin (36). This enzyme is a serine protease, and its mechanism of catalysis may be outlined as follows, where or R2 preferentially is a hydrophobic amino acid residue. 

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