Graça José, Santos Sara
Instituto Superior de Agronomia, Departamento de Engenharia Florestal, Universidade Técnica de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal.
Biomacromolecules. 2006 Jun;7(6):2003-10. doi: 10.1021/bm060174u.
Cork suberin was partially depolymerized by methanolysis catalyzed by calcium hydroxide. Analysis by GC-MS of the methanolysate showed suberin monomers, including glycerol and long-chain alpha,omega-diacids and omega-hydroxyacids. ESI-MS analysis of the methanolysate showed, besides the aliphatic monomers, suberin oligomers, including linear dimeric esters of alpha,omega-diacids and omega-hydroxyacids. Two types of dimeric esters were identified: a alpha,omega-diacid linked to a omega-hydroxyacid and two inter-linked omega-hydroxyacids. The alpha,omega-diacids and omega-hydroxyacids found as monomer residues in the dimeric esters were mainly the C18 monomers with midchain substituents. The identification of these dimeric esters was based in their CID-MS/MS spectra and confirmed after synthesis of model compounds. The occurrence of inter-esterified long-chain monomers in suberin brings a new insight in the understanding of the polyester structure of this biopolymer.
通过氢氧化钙催化的甲醇解作用，软木栓质发生了部分解聚。对甲醇解产物进行气相色谱 - 质谱分析，结果显示栓质单体，包括甘油、长链α,ω - 二元酸和ω - 羟基酸。对甲醇解产物进行电喷雾电离质谱分析，结果显示除了脂肪族单体之外，栓质低聚物也存在，包括α,ω - 二元酸和ω - 羟基酸的线性二聚酯。鉴定出了两种类型的二聚酯：一种是连接到ω - 羟基酸的α,ω - 二元酸，以及两个相互连接的ω - 羟基酸。在二聚酯中作为单体残基发现的α,ω - 二元酸和ω - 羟基酸主要是带有链中取代基的C18单体。这些二聚酯的鉴定基于它们的碰撞诱导解离串联质谱光谱，并在合成模型化合物后得到了证实。栓质中存在酯交换长链单体，为理解这种生物聚合物的聚酯结构带来了新的见解。
