The association of proteins with polyphenols

A Mathematical Model Describing Tannin–Protein Association

“…This has given rise to a separate group of analytical methods, which measure natural polyphenols (tannins) based on their ability to precipitate proteins (12)(13)(14)(15)(16)(17)(18). It has been found that the number of tannin molecules bound per protein molecule in the precipitate formed with phenols depends markedly on the protein concentration; generally, the lower the protein concentration, the greater the tannin/protein ratio (19,20). It has also been found that precipitation is followed by resolubilization of the tannin-protein complex upon further addition of protein (21,22).…”

The Metabolism of Gallic Acid and Hexahydroxydiphenic Acid in Higher Plants

“…Overwhelming circumstantial evidence points unmistakably to the fact that these properties derive from the accumulation, within a molecule of moderate molecular size, of a substantial number of unconjugated phenolic groups with an ortho-dihydroxy (catechol) or ortho-trihydroxy (pyrogallol) orientation. Recent experimental work supports this suggestion (53). The affinity of resorcinol for proteins is weak but with catechol, pyrogallol and methyl gallate the binding to protein is considerably enhanced, both in its strength and in the number of primary and secondary sites on the molecule which are available for complexation.…”

Condensed Tannin Intake in Spiny-Forest-Dwelling Lemur catta at Berenty Reserve, Madagascar, during Reproductive Periods

“…Even though protein requirements of reproductive mammalian females are far higher than those of non-reproductive animals [Lee, 1996;Jessops, 1997], and CTs bind with both protein and iron and interfere with their uptake [Ramachandra et al, 1977;Roy and Mukherjee, 1979;Choo et al, 1981;McManus et al, 1981;Spelman et al, 1989;Chapman and Chapman, 2002;Lambert, 2007], the pregnant and lactating females in this study did not consume foods lower in CT compared with adult males. Waterman [1984] and Waterman and Kool [1994] point out that tannins do not necessarily bind all proteins equally and can, in some cases, enhance protein hydrolysis.…”

“…Tannins are naturally occurring water-soluble phenolic compounds which, when ingested, can interfere with nutrient and iron uptake, particularly that of nitrogen (protein), as they bind with plant proteins and iron and prevent absorption [Ramachandra et al, 1977;Roy and Mukherjee, 1979;McManus et al, 1981;Choo et al, 1981;Spelman et al, 1989;Chapman and Chapman, 2002;Lambert, 2007]. Plants containing tannins are astringent and unpalatable, an adaptation to deter consumption by herbivores [Janzen, 1974;McKey et al, 1978;Chapman and Chapman, 2002].…”