Enzymes digestive juices

Enzymes may be described a organic catalysts of biological origin. The majority are obtained from the interior of cells, but some are obtained from natural secretions such as the digestive juices and milk. For a full discussion of the nature of enzymes and the mechanism of their reactions the student should consult a work such as Chemistry and Methods of Enzymes, by J. B. Sumner and G. F. Somers (Academic Press, New York), or Enzymes, by M. Dixon and E. C. Webb[(Longman Group Ltd.). The following points should however be noted ... 

Other compounds in the fresh leaves may act synergistically in creating the extraordinary and variable effects of this plant, perhaps by inhibiting the lytic action of an enzyme or ofthe digestive juices. 

The enzymatic hydrolysis is the method of choice when undesired reactions are to be avoided. /Tglucosidases (or /J-glucuronidases) from Helix pomatia digestive juice are now commercially available. They usually show a good hydrolytic performance, even if sometimes need long time reactions (days). Other enzymes are reported to have been used to specifically hydrolize saccharidic bonds like hesperidinase, /J-xylosidase, j3-galactosidase, and mixed crude enzymes like cellulase. 

Barry114 isolated a disaccharide, laminaribiose, on the partial hydrolysis of laminarin by enzymes (digestive juice of the snail Helix pomatia or H. aspersa) or by acid (seven hours with N oxalic acid on the water-bath). He showed that this disaccharide consisted solely of D-glucose and considered it to be 3-j3-D-glucopyranosyl-D-glucopyranose (XXIX). 

Papayas contain papain, an enzyme that is similar to the digestive juice pepsin. Because this enzyme breaks down protein, papain extract from papayas is marketed as a meat... 

The known sources which most closely approach the female-rat preputial gland in activity are the digestive juices of molluscs and of locusts. As shown for the rumen of the sheep,100 the contents of the mammalian large intestine probably owe most of their /8-glucuronidase activity to microbes, whilst in the small intestine the enzyme is probably mammalian in origin.40... 

The physiological action of the cinchona alkaloids is that of an antipyretic or febrifugCj lowering the body temperature in case of fevers. Quinine retards the action of oxidase enzymes and acts as a poison to certain organisms, especially that of malaria. Its first use was as a specific for this form of fever. It has a very bitter taste and in common with other substances of like properties it acts on the alimentary canal causing increased secretion of digestive juices. 

The normal range of serum zinc in the adult is 11 to IS pM- Urinary zinc is 3(1(1 to 700 pg/day, which is equivalent to 2 to of zinc intake. Most of the absorbed zinc is excreted in the bile and is eventually lost In the feces. Fecal zinc originates from nonabsorbed zinc and from pancreatic secretions and exfoliated enterocyles-The zinc released by the pancreas can be reabsorbed and thus participates in enteropancreatic circulation. Nearly all of the zinc in pancreatic juices is bound to carboxypeptidase A and b. About 1 mg of fecal zinc per day is derived from pancreatic secretions. In any accounting of the nutrients absorbed each day, one needs to realize that the enzymes and salts released in the digestive juices each day (during a meal) actually represent a second meal. The digestive enzymes, for... 

Bile acid glucuronides may be hydrolyzed by -glucuronidase (EC 3.2.1.31) from bovine liver or the digestive juice of Helix pomatia (S41). The latter enzyme preparation also contains sulfatase activity (S41), but this is likely to be an aryl sulfatase which may not use bile acid sulfates as substrates. 

Seine enzymes have optima as high as 9 or 10, whilst others, such as the pepsin of stomach digestive juice, function at the high acidity of pH 2-3. 

The nudeo-proteins under the influence of enzymes are successively transformed into nucleins, into nudeic adds, then into xanthin bases, into phosphoric acid, etc. But only the first phase of the transformation, that which corresponds to the formation of protein and nudein, can be realized by p>epsin and trypsin. The nudeins resist the action of the digestive juices, botii gastric arid pancreatic. The transformation of the nucleins first into nucldc adds, then into phosphoric add and into purin bas, is induced in living cells, on the contrary, by the endo-cellular enzymes, which bear the name of nucleases. 

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