Purification and complete amino acid sequence of a new type of sweet protein taste-modifying activity, curculin.
Purification and complete amino acid sequence of a new type of sweet protein taste-modifying activity, curculin.
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新型甜味蛋白矫味活性仙茅素的纯化和完整氨基酸序列。
DOI：
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发表时间：
1990
影响因子：
4.8
通讯作者：
Yoshie Kurihara
中科院分区：
文献类型：
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作者：
H. Yamashita;S. Theerasilp;T. Aiuchi;Kazuyasu Nakaya;Y. Nakamura;Yoshie Kurihara
用0.5M NaCl溶液从宽叶仙茅果实中提取一种新的矫味蛋白，命名为仙茅素，经硫酸铵分级沉淀、CM-Sepharose离子交换层析和凝胶过滤纯化。由此获得的纯化仙茅素在8 M尿素存在下在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳上得到一条Mr为12，000的单一条带。通过低角激光散射测定的分子量为27，800。这些结果表明，天然仙茅素是12，000-Da多肽的二聚体。采用Edman自动降解法测定仙茅素的氨基酸序列。仙茅素由114个残基组成。仙茅素本身有甜味。仙茅素之后，水会产生甜味，而酸味物质会产生更强烈的甜味。目前还没有发现既具有甜味又具有矫味活性的蛋白质，其中有五组三肽与神秘果蛋白（一种矫味蛋白）相同，六组三肽与索马甜蛋白（一种甜味蛋白）相同，两组三肽与莫内林蛋白（一种甜味蛋白）相同。抗神秘果蛋白血清与仙茅素无免疫反应。并对仙茅素的矫味作用机理进行了讨论。
A new taste-modifying protein named curculin was extracted with 0.5 M NaCl from the fruits of Curculigo latifolia and purified by ammonium sulfate fractionation, CM-Sepharose ion-exchange chromatography, and gel filtration. Purified curculin thus obtained gave a single band having a Mr of 12,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the presence of 8 M urea. The molecular weight determined by low-angle laser light scattering was 27,800. These results suggest that native curculin is a dimer of a 12,000-Da polypeptide. The complete amino acid sequence of curculin was determined by automatic Edman degradation. Curculin consists of 114 residues. Curculin itself elicits a sweet taste. After curculin, water elicits a sweet taste, and sour substances induce a stronger sense of sweetness. No protein with both sweet-tasting and taste-modifying activities has ever been found. There are five sets of tripeptides common to miraculin (a taste-modifying protein), six sets of tripeptides common to thaumatin (a sweet protein), and two sets of tripeptides common to monellin (a sweet protein). Anti-miraculin serum was not immunologically reactive with curculin. The mechanism of the taste-modifying action of curculin is discussed.