López-Franco Yolanda L, Valdez Miguel A, Hernández Javier, Calderón de la Barca Ana M, Rinaudo Marguerite, Goycoolea Francisco M
Laboratory of Biopolymers, Centro de Investigación en Alimentación y Desarrollo, A.C. (C.I.A.D., A.C.) P.O. Box 1735 Hermosillo, Sonora, 83000, Mexico.
Macromol Biosci. 2004 Sep 16;4(9):865-74. doi: 10.1002/mabi.200400055.
Mesquite gum sourced from Prosopis velutina trees and gum arabic (Acacia spp.) were characterized using light scattering and Langmuir isotherms. Both gum materials were fractionated by hydrophobic interaction chromatography, yielding four fractions for both gums: FI, FIIa, FIIb and FIII in mesquite gum and FI, FII, FIIIa and FIIIb in gum arabic. In mesquite gum, the obtained fractions had different protein content (7.18-38.60 wt.-%) and macromolecular dimensions (M approximately 3.89 x 10(5)-8.06 x 10(5) g.mol(-1), RG approximately 48.83-71.11 nm, RH approximately 9.61-24.06 nm) and architecture given by the structure factor (RG/RH ratio approximately 2.96-5.27). The mechanical properties of Langmuir monolayers at the air-water interface were very different on each gum and their fractions. For mesquite gum, the most active species at the interface were those comprised in Fractions IIa and IIb and III, while Fraction I the pi/A isotherm lied below that of the whole gum. In gum arabic only Fraction III developed greater surface pressure at the same surface per milligram of material than whole gum. This is rationalized in terms of structural differences in both materials. Mesquite gum tertiary structure seems to fit best with an elongated polydisperse macrocoil in agreement with the "twisted hairy rope" proposal for arabinogalactan proteoglycans.
对源自绒毛牧豆树的牧豆树胶和阿拉伯树胶（阿拉伯胶属）进行了光散射和朗缪尔等温线表征。两种胶原料均通过疏水相互作用色谱法进行分级分离，牧豆树胶和阿拉伯树胶都得到了四个级分：牧豆树胶的FI、FIIa、FIIb和FIII，以及阿拉伯树胶的FI、FII、FIIIa和FIIIb。在牧豆树胶中，所得到的级分具有不同的蛋白质含量（7.18 - 38.60 wt.-%）和大分子尺寸（M约为3.89×10⁵ - 8.06×10⁵ g·mol⁻¹，RG约为48.83 - 71.11 nm，RH约为9.61 - 24.06 nm）以及由结构因子给出的结构（RG/RH比值约为2.96 - 5.27）。在空气 - 水界面处，朗缪尔单分子层的力学性能在每种胶及其级分上有很大差异。对于牧豆树胶，界面处最具活性的物种是包含在FIIa、FIIb和III级分中的那些，而I级分的π/A等温线低于整个胶的等温线。在阿拉伯树胶中，仅III级分在每毫克材料的相同表面上比整个胶产生更大的表面压力。这可以根据两种材料的结构差异来解释。牧豆树胶的三级结构似乎最符合细长的多分散大线圈，这与阿拉伯半乳聚糖蛋白聚糖的“扭曲毛绳”提议一致。
