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α-D(+)-Glucose pentaacetate

α-D(+) - 葡萄糖五乙酸酯

Company: Sigma-Aldrich
Catalog#: G2354
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Assays for Determination of Acetylesterase Activity and Specificity Using pNP-acetyl and Acetylated Polysaccharides as Substrates
[Abstract]  The acetylesterases are hydrolytic enzymes which in plants cleave acetyl groups from acetylated cell wall components, primarily polysaccharides. To estimate acetylesterase activity in plant apoplast, two assays can be used. First assay is a direct measurement of the acetylesterase activity in protein extract using synthetic substrate, pNP-acetyl. In this assay, amount of pNP released after hydrolysis of pNP-acetyl is determined by measuring the intensity of developed yellow color using spectrophotometer. The absorbance of reaction mixture is directly proportional to the activity of acetylesterases in the reaction mixture. Second assay is a determination of acetylesterase activity and its specificity towards natural polysaccharides and based on interaction between ferric perchlorate and ... [摘要]  乙酰酯酶是水解酶,其在植物中从乙酰化的细胞壁组分,主要是多糖中切割乙酰基。为了估计植物质外体中的乙酰酯酶活性,可以使用两种测定。第一个测定是使用合成底物,pNP-乙酰基直接测量蛋白质提取物中的乙酰酯酶活性。在该测定中,通过使用分光光度计测量显色黄色的强度来确定pNP-乙酰基水解后释放的pNP的量。反应混合物的吸光度与反应混合物中乙酰酯酶的活性成正比。第二个测定是乙酰酯酶活性及其对天然多糖的特异性的测定,并且基于高氯酸铁和乙酰基残基之间的相互作用,导致可以使用分光光度计定量的乙酰氧肟酸络合物。在该测定中,使用高粱酸铁试剂来估计与质外体提取物孵育的市售乙酰化多糖(来自Birchwood的木聚糖用于乙酰木聚糖酯酶的果胶;来自柑橘属水果的用于鼠李半乳糖醛酸聚糖乙酰酯酶的果胶;或任何其他可用的目的多糖)和量的从该多糖中释放的乙酰基残基,试剂(方案由McComb和McCready,1957修改)。产生的有色复合物的吸光度与从乙酰化多糖释放的乙酰基的量成正比。