Peptic-tryptic digest

Fractionation of Wheat Gluten Complete acid hydrolysis of the gluten results in loss of its deleterious properties. Deamidation by acid or by treatment with papain (K6) also markedly reduces its toxic action on patients with gluten-induced enteropathy. However, peptic/tryptic digestion does not significantly reduce toxicity (F27). This might be expected from the fact that... 

Bolte G, Osman A, Mothes T, Stern M. Peptic-tryptic digests of gliadin Contaminating trypsin but not pepsin interferes with gastrointestinal protein binding characteristics. Clin Chim Acta 1996 247 59-70. 

Haddad, Z. H., Kalra, V., and Verma, S., 1979, IgE antibodies to peptic and peptic-tryptic digests of P lactoglobulins significance in food hypersensitivity. Annals of Allergy 42 368. 

Figure 1.9 Autoradiographs obtained after electrophoresis at pH 3.5 of peptic-tryptic digests of partially reduced and carboxymethylated G myeloma proteins of different subclasses, IgM macroglobulins, and A, D and E myeloma proteins. k peptide derived from the C-terminal of L chains k type). A1 and A2 are two related peptides derived from the C-terminal of L chains (A type). Each H chain gives a specific autoradiographic pattern due to differences in the peptides derived from the inter H—H or inter H—L disulphide bonds . ...

Peptic and tryptic digestion of Type I pneumococcal cells, followed by alcoholic precipitation and subsequent removal of the nucleic acid, gave SI in 92-98% purity. Hydrolysis (with N sulfuric acid at 100°) liberated galactose and fucose within 15 minutes, followed by 2-amino-2-deoxy-D-glucose (in one hour) and galacturonic acid (in 6-8 hours). Quantitative immunological data were not given for the preparation. 

Ammoniacal Nitrogen Formed in Peptic and Tryptic Digestions... 

Accumulations of Amino-acids in the Course of Peptic, Tryptic, AND Ereitic Digestions. 

Fragments of BSA (obtained from peptic or tryptic digests) corresponding to the sequences 1-385, 198-581, 1-306, 307-581, 377-581, 49-185, 186-306, 307-385, 504-581, and 115-184 showed CD spectra similar to the spectrum of BSA, indicating very little conformational variations (Reed eta/., 1975). 

Whenever the calculated biological value was compared to experimental determinations of the biological value, the two values were found to be extremely close. Such mathematical formulas are limited by the fact that the proteins are not all digested at equal rates. This difficulty has been overcome by estimating the amino acid composition not directly after total hydrolysis of the protein, but on the product of peptic and tryptic digestion of the protein. Such experiments have revealed that whereas the amino acids of the proteins contained in roast beef or wheat or peanut flour are readily available, the amino acids of cotton seed flour are not [27]. 

A number of zoopolysaccharides have been isolated in purified condition and the structures partially established. Many of these are bound with other tissue components in the natural condition. They are isolated from the macerated tissues or the secretions by extraction with alkalies or salts (especially calcium chloride). Mucins and many mucoids are precipitated by weak acids, and their polysaccharide components are subsequently recovered. If dissociable, proteins may be removed by precipitation with amyl alcohol - chloroform (Sevag) or formaldehyde (Masamime). Peptic or tryptic digestion may remove these and covalently bound proteins. Colorimetric, chromatographic, and isolation methods have been used for the identification of the component sugars (, 14, 15-16h), (See also imder Glucosamine, Chapter VIII, Uronic acids. Chapter VI and part I, Chapter XII.)... 

This scheme of analysis is useful for the examination of artificial mixtures and peptic and tryptic digestion products. It does not differentiate between albumin and globulin or between proteose and peptone when present along with other higher and lower proteins. Such differentiation can be accomplished best by fractional precipitation with neutral salts, supplemented by the foregoing tests. 

The difference between the peptic and tryptic reactions becomes still more evident when we compare the products of these two digestions brought to the same degree of hydrolysis, a condition estimated according to the value of the formaldehyde figure. 

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