Digestibility, protein, effect

Feeny (13) attempted to resolve this dilemma by proposing that forest trees may have developed a particularly recalcitrant defense, one which even insects could not overcome in hundreds of generations. His suggestion was that protein-complexing polyphenols, or tannins, could provide such protection. However, there are many insects which feed preferentially on high-tannin content tissues (14, ), and specific adaptations exist which can nullify or reduce the digestion inhibition effects of tannins (16). ... 

Proteolytic enzymes cleave specific amino acid sequences within the peptide chain of the digested protein since proteases differ in their cleavage specificities, they can have markedly different effects upon tissues depending upon the type of fixative used for processing the tissue, the antigenic target, and the epitope recognized by the antibody. 

Changes in the number of free amino residues alter the modified proteins susceptibility to proteolysis. Albumin chlorination and /V-chloramine formation decreases susceptibility to trypsin digestion. Removing of chloramine residues by treatment with thiosulfate shows that chlorination alters albumin properties by a biphasic mode the reversible chlorination and removal of chloramine moieties markedly increases albumin susceptibility to proteolysis, whereas chlorination produces the irreversible loss of amino moieties and carbonyl group formation effects decrease in albumin susceptibility to trypsin digestion. The effect is related to the number of lost amino residues. A similar relationship was observed for IgG. Fibrinogen and protamine, on the other hand, did not show dependence between chlorination and proneness to trypsin proteolysis (06). 

Interactions between tannins and proteins have been extensively studied (Hager-man 1989 Haslam and Lilley 1988 Haslam et al. 1992), owing to their role in haze formation, astringency perception, and nutritional and anti-nutritional effects resulting from inhibition of various enzymes and reduction of dietary protein digestion. Other effects include reduced adsorption of /3-casein at the air-liquid interface in the presence of epigallocatechin gallate with potential consequences on foam properties (Sausse et al. 2003). 

Venkatachalam, M., Tenber, S.S., Peterson, W.R., Roux, K.H., and Sathe, S.K., Antigenic stability of pecan [Carya illinoinensis (Wangenh.) K. Koch] proteins Effects of thermal treatments and in vitro digestion, J. Agric. Food Chem., 54, 1449-1458, 2006. 

Treatment of slides with pepsin can increase probe reagent accessibility by digesting proteins. It is particularly effective if cytoplasm is associated with the chromosome preparations. Time and concentration of the pepsin treatment might need to be adjusted for different material. If the chromosome preparations are very clean, it can be left out (steps 4-6 of Section 3.1.). 

Insoluble peptides produeed from tryptic or cyanogen bromide-digested proteins were effectively analyzed by SEC with SDS in the mobile phase to separate families of peptides that could subsequently be analyzed by gel electrophoresis or another technique [54]. Complexes between heat shock proteins and unfolded substrate proteins have also been monitored successfully using SEC [55]. The effect of ATP and ADP on the complexation could be readily ascertained with this technique. 

Table II. Effect of alkaline treatment on the relative rate of amino acids release after 3, 6 and 24 h of protein digestion (protein (N) digestibility at a given time = 1) ... 

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