Laboratory of Industrial Biotechnology, Institute of Bioscience, Universiti Putra Malaysia , 43400 UPM, Serdang, Malaysia.
J Agric Food Chem. 2011 Oct 12;59(19):10677-82. doi: 10.1021/jf201925g. Epub 2011 Sep 19.
Depending on their source, concentration, chemical structure, and molecular weight, condensed tannins (CTs) form insoluble complexes with protein, which could lead to ruminal bypass protein, benefiting animal production. In this study, CTs from Leuceana leucocephala hybrid were fractionated into five fractions by a size exclusion chromatography procedure. The molecular weights of the CT fractions were determined using Q-TOF LC-MS, and the protein-binding affinities of the respective CT fractions were determined using a protein precipitation assay with bovine serum albumin (BSA) as the standard protein. The calculated number-average molecular weights (M(n)) were 1348.6, 857.1, 730.1, 726.0, and 497.1, and b values (the b value represents the CT quantity that is needed to bind half of the maximum precipitable BSA) of the different molecular weight fractions were 0.381, 0.510, 0.580, 0.636, and 0.780 for fractions 1, 2, 3, 4, and 5, respectively. The results indicated that, in general, CTs of higher molecular weight fractions have stronger protein-binding affinity than those of lower molecular weights. However, the number of hydroxyl units within the structure of CT polymers also affects the protein-binding affinity.
根据其来源、浓度、化学结构和分子量，缩合单宁（CTs）与蛋白质形成不溶性复合物，这可能导致瘤胃旁路蛋白，有益于动物生产。在这项研究中，Leuceana leucocephala 杂种的 CTs 通过排阻色谱程序分离成五个部分。使用 Q-TOF LC-MS 测定 CT 部分的分子量，并使用牛血清白蛋白（BSA）作为标准蛋白的蛋白沉淀测定法测定各自 CT 部分的蛋白结合亲和力。计算得到的数均分子量（M(n)）分别为 1348.6、857.1、730.1、726.0 和 497.1，不同分子量部分的 b 值（b 值表示与最大可沉淀 BSA 结合一半所需的 CT 量）分别为 0.381、0.510、0.580、0.636 和 0.780，分别为第 1、2、3、4 和 5 部分。结果表明，一般来说，高分子量部分的 CTs 比低分子量部分具有更强的蛋白结合亲和力。然而，CT 聚合物结构内的羟基单元数量也会影响蛋白结合亲和力。
