Division of Biological Sciences, University of Michigan, 48109, Ann Arbor, Michigan.
J Chem Ecol. 1985 Apr;11(4):485-94. doi: 10.1007/BF00989559.
Tannic acid and pin oak tannins precipitate large amounts of the abundant leaf protein, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPC), over a wide pH range (6.15-9.30) in the presence of sodium, potassium, magnesium, and calcium ions at concentrations comparable to those reported in the gut fluids of lepidopteran herbivores. The presence of lysolecithin, a surfactant known to be present in the gut fluids of some insects, significantly reduces the amount of RuBPC precipitated under these conditions. We conclude that high detergency is far more effective than high alkalinity in countering the potential protein-precipitating properties of tannins. We further conclude that tannins do not deserve the status they were once accorded as general, all-purpose, dose-dependent, antidigestive defensive chemicals. We also describe the application of the Schaffner-Weissman protein assay for studying the protein-precipitating capacity of plant extracts. This method is far superior to the one we have used in our earlier studies.
单宁酸和栓皮栎单宁在钠离子、钾离子、镁离子和钙离子存在的情况下，在较宽的 pH 范围（6.15-9.30）内沉淀大量丰富的叶蛋白，核酮糖-1,5-二磷酸羧化酶/加氧酶（RuBPC）。浓度与鳞翅目植食性昆虫肠道液中报道的浓度相当。溶血卵磷脂是一种已知存在于某些昆虫肠道液中的表面活性剂，它的存在显著减少了在这些条件下沉淀的 RuBPC 的量。我们得出的结论是，高去污力远比高碱性更能有效抵抗单宁潜在的蛋白质沉淀特性。我们进一步得出结论，单宁不应享有它们曾经被赋予的作为通用、多用途、剂量依赖性、抗消化防御性化学物质的地位。我们还描述了 Schaffner-Weissman 蛋白质测定法在研究植物提取物的蛋白质沉淀能力中的应用。这种方法比我们之前研究中使用的方法优越得多。
