Bromelain enzymic activity

For soluble and immobilized bromelain, temperature increase is accompanied by a decrease in residual enzyme activity. A more complex form of... 

Dissolve a suitable amount of bromelain HP standard in enzyme-activation solution to obtain a solution with an activity of apparently 0.1-0.12 FI.P, units/mL. 

A fibrinolysis enzyme activator was isolated from commercial bromelain [28]. The active substance has no intrinsic fibrinolytic activity, nor any... 

For soluble and immobilized bromelain, temperature increase is accompanied by a decrease in residual enzyme activity. A more complex form of denaturation occurs with the immobilized enzyme, which may involve a two-phase process. Immobilization offers more resistance to denaturation at the higher temperature of 60°C where the second phase is prolonged by a factor of three [60]. Differential scanning calorimetry experiments showed that bromelain is an exceptional protease among the cysteine proteases, illustrated by the fact that its thermal denaturation is consistent with an irreversible two-state model [61]. Also, the far UV circular dichroism spectrum of bromelain differs from those of papain and chymopapain and therefore represents a third spectral class within the cysteine proteinase family [62],... 

Tappel (99) reported on the hydrolytic activity of various enzymes. They found that the relative hydrolysis of muscle proteins increased in the following order pepsin, Rhozyme A-4, ficin, papain, bromelain, protease 15, Rhozyme P-11, and trypsin. Wang et al. (100) observed that papain was twice as active as ficin towards elastin, a minor component of connective tissue. Ficin and bromelain had equal enzyme activity towards collagen, a major component of connective tissue. Kang and Rice (101) studied the effects of various tenderizing enzymes on water-soluble sarcoplasmic proteins, salt-soluble myofibrillar proteins, and the insoluble stromal proteins. Table VII tabulates the results of some of these studies. 

Moore, 1978). The conformation of the polypeptide chain is also remarkably similar to that of papain (Baker, 1977). Actinidin is thus classified in a member of the papain superfamily, which includes papain and bromelain, and the mammalian cathepsins B, K, and L. The optimal pH of actinidin is about 4 when using food proteins such as gelatin (Arcus, 1959) or myofibrillar proteins (Nishiyama, 2001) as the substrate. The optimal pH is around 6 when the enzyme activity is measured with synthetic peptides as the model substrates (Boland and Hardman, 1972 Boyes et al, 1997 McDowall, 1970 Sugiyama et al, 1997). Regardless of this accumulated knowledge, nothing is known as yet about the physiological function of actinidin in fruits. 

Pancreatin is a pancreatic extract usually obtained from the pancrease of slaughterhouse animals. It contains a mixture of enzymes, principally amylase, protease and lipase, and, thus, exhibits a broad digestive capability. It is administered orally mainly for the treatment of pancreatic insufficiency caused by cystic fibrosis or pancreatitis. As it is sensitive to stomach acid, it must be administered in high doses or, more usually, as enteric-coated granules or capsules that may be taken directly or sprinkled upon the food prior to its ingestion. Individual digestive activities, such as papain, pepsin or bromelains (proteases), or a-amylase are sometimes used in place of pancreatin. 

In the course of investigations using 4-chloro-7-nitrobenzofurazan as a reactivity probe for identifying the active sites of a number of enzymes such as papain, ficin, and bromelain, the intermediacy of Meisenheimer adducts derived from direct attack of thiolate groups located in the protein has been assumed on the basis of the spectral changes accompanying the process of replacement of the chloro group.232,233... 

Oral administration of bromelain to rats resulted in an increase in proteolytic activity in blood [82]. Seifert et al, [S3] administered radioactive bromelain via the duodenum to rata. They proved that 40% of the radioactively tagged bromelain was absorbed in its high molecular weight form in blood and lymph. The enzyme was identified using anti bromelain antiserum raised in rabbits. They claimed that a proteolytic enzyme of about 28,000 daltons passed into the blood and then exerts its physiological action [84]. 

Among the proteolytic enzymes, the plant proteases are the most widely used in the food industry. Most of the plant proteases which have been studied are characterized by a free sulfhydryl group which is essential for their activity. The most important of these so-called sulfhydryl or thiol proteases are papain, ficin, and bromelain. Since the literature on these enzymes has been the subject of several recent reviews (i, 2, 3, 4), major emphasis is placed in this presentation on the use of these enzymes in the food industry. Some of the more recent developments relating to the structure and function of the sulfhydryl proteases are discussed. 

Proteolytic activity in the juice of the pineapple plant Ananas comosus) was first reported in 1879 (7). More recently, the juice from the stem of the pineapple plant was shown to be a rich source of stem bromelain. This name is used to distinguish the enzyme from another which is derived from the fruit (8, 9). Mature pineapple stems are collected by special harvesting machines. The juice is pressed by special mills and then filtered. Most commercial preparations of bromelain have been precipitated from the stem juice by acetone. 

Inhibition. Since papain, ficin, and bromelain are all enzymes whose activity depends on a free SH group, it is to be expected that all thiol reagents act as inhibitors. Thus, a-halogen acids or amides and N-ethyl-maleimide irreversibly inhibit the thiol proteases. Heavy metal ions and organic mercurial salts inhibit in a fashion that can be reversed by low molecular weight thiols, particularly in the presence of EDTA which... 

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