Polymerization degrees, molecular weights and protein-binding affinities of condensed tannin fractions from a leucaena leucocephala hybrid

Mookiah Saminathan, and Hui , Yin Tan and Chin , Chin Sieo and Norhani Abdullah, and Vui Ling Wong , Clemente Michael and Emilia Abdulmalek, and Yin , Wan Ho (2014) Polymerization degrees, molecular weights and protein-binding affinities of condensed tannin fractions from a leucaena leucocephala hybrid. Molecules, 19 (6). pp. 7990-8010. ISSN 1420-3049

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Official URL: http://dx.doi.org/10.3390/molecules19067990

Abstract

Condensed tannins (CTs) form insoluble complexes with proteins and are able to protect them from degradation, which could lead to rumen bypass proteins. Depending on their degrees of polymerization (DP) and molecular weights, CT fractions vary in their capability to bind proteins. In this study, purified condensed tannins (CTs) from a Leucaena leucocephala hybrid were fractionated into five different molecular weight fractions. The structures of the CT fractions were investigated using 13C-NMR. The DP of the CT fractions were determined using a modified vanillin assay and their molecular weights were determined using Q-TOF LC-MS. The protein-binding affinities of the respective CT fractions were determined using a protein precipitation assay. The DP of the five CT fractions (fractions F1-F5) measured by the vanillin assay in acetic acid ranged from 4.86 to 1.56. The 13C-NMR results showed that the CT fractions possessed monomer unit structural heterogeneity. The number-average molecular weights (Mn) of the different fractions were 1265.8, 1028.6, 652.2, 562.2, and 469.6 for fractions F1, F2, F3, F4, and F5, respectively. The b values representing the CT quantities needed to bind half of the maximum precipitable bovine serum albumin increased with decreasing molecular weight-from fraction F1 to fraction F5 with values of 0.216, 0.295, 0.359, 0.425, and 0.460, respectively. This indicated that higher molecular weight fractions of CTs from L. leucocephala have higher protein-binding affinities than those with lower molecular weights. © 2014 by the authors.

Item Type:Article
Uncontrolled Keywords:Condensed tannins; Degree of polymerization; Leucaena leucocephala; Molecular weight; NMR; Protein-binding affinity; Q-TOF LC-MS
Subjects:Q Science > QD Chemistry
ID Code:10321
Deposited By:IR Admin
Deposited On:06 Feb 2015 09:43
Last Modified:17 Feb 2015 11:31

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