Tannin activity protein binding

Condensed Units Derived from Proanthocyadin Units Biological Activity of Tannins Binding of Tannins to Protein Tannins in the Diets of Animals The Cost of Tannin Defenses and Resource Allocation Other Proposed Functions of Tannins Medicinal Properties of Tannins Correlation of Tannin Consumption and Throat Cancer Tannins and the Production of Leather Other Types of Tannins Analysis of Tannins References... 

Figure 4. Binding of a protein (hemoglobin) to several tannin extracts (tannic acid, sugar maple tannins, yellow birch tannins, quebracho tannins see 29) at various pH values. Ranges of microbial chitinase activity, NPV activity, and Bt toxicity are given. See text for discussion and references.

To maintain stable complexes with proteins, phenolic molecules must be relatively large so that they can form enough bonds with the protein molecules however, if the tannin molecule is too large, it will be unable to bind with the active sites on the protein, and bonding will be less likely. Finally, protein-tannin complexes are more stable, and the tannin qualities are highest when the molecular weight of the tannins is between 500 and 3000. 

Tannins are a broad class of complex phenolic compounds that are comprised of two chemical groups the hydrolyzable tannins (gallotannins) and the condensed tannins (proanthocyanidins). Tannins bind to and precipitate proteins, producing the astringent activity of tannin-containing herbs. Tannins are natural components of many herbs and common foods, and some tannins are used in the processing of foods, alcoholic beverages, and medicines. 

The therapeutic activities of tannins are associated with their ability to bind with and precipitate proteins and to force dehydration of mucosal tissues. In external use, these actions allow the formation of a protective layer of harder. 

Vegetable tans, however, are based on wood, bark, leaves and roots of mimosa, quebracho, chestnut and oak. - Tannin is the active ingredient, a polyphenol (sugar derivative of gallic acid), which binds to the collagen (- proteins) by hydrogen bonds. Due to a m.w. of 500-5000, the penetration into the fibrils is slower than with chromium tans and results in heavier and fuller leathers. 

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