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Syntheses of Umami Peptides with Immobilized Papain in Water-Immiscible Organic Solvent Systems

与水不混溶的有机溶剂体系中固定木瓜蛋白酶合成鲜味肽

基本信息

批准号：
01560151
负责人：
NAKANISHI Kazuhiro
金额：
$ 1.41万
依托单位：
Okayama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

项目摘要

Dipeptides such as L-glutamic acid dimer and L-glutamic acid dimer are known as a substance posessing umami (brothy) taste and a bitter taste masking effect. In this study, we attempted to synthesize precursors of four peptides, i. e., GluGlu, GluAsp, AspGlu, and AspAsp with an immobilized papain in organic solvent systems. As an acid component of a substrate, N-(benzyloxycarbonyl)-L-glutamic acid and N-(benzyloxycarbonyl)-L-aspartic acid, and as an amine component L-glutanic acid diethyl ester and L-aspartic acid diethyl ester were used. In most cases, we focussed on the synthesis of N-(benzyloxycarbonyl)-L-glutamyl-L-glutamic acid diethyl ester (Z-GluGlu(OEt)_2) at 30 ^ﾟC.The results obtained are Summarized as follows :1) The synthetic reaction did not take place in buffer solution.2) In the aqueous-organic biphasic reaction systems with ethyl acetate as an organic solvent, the maximum yield of Z-GluGlu (OEt) _2 reached about 70%.3) The enzyme was immobilized onto various porous supp … More orts. The enzyme was first adsorbed onto the support and then cross-linked with glutaraldehyde. The highest activity was obtained when the enzyme was adsorbed onto porous ceramic support (SM10-C1, Nippon Gaishi K. K.).4) The activity of immobilized enzyme depended strongly on the water content in an outer organic solvent. The highest activity was obtained at a water content of 2.5% with the enzyme immobilized onto SM10-C1.5) L-Glutamic acid diethyl ester, an amine component of the substrate was non-enzymatically coverted to L-pyroglutamic acid diethyl ester. To reduce the effect of non-enzymatic reaction, the increase of the concentration of the immobilized enzyme was found most effective. With 100 mM Z-Glu and 200 mM Glu (OEt) _2, and immobilized enzyme concentration of 8%, the yield became higher than 90%.6) The other three dipeptides precursors were also obtained with quite a high yield under the same reaction conditions as shown in (5).7) The products were identified by analyzing with nuclear magnetic resonance, mass spectrum, and infrared adsorption spectrum. Less

已知二肽如L-谷氨酸二聚体和L-谷氨酸二聚体是具有鲜味（肉汤味）和苦味掩蔽作用的物质。在本研究中，我们尝试合成四种多肽的前体，例如，GluGlu、GluAsp、AspGlu和AspAsp与固定化木瓜蛋白酶在有机溶剂系统中的反应。作为底物的酸成分，使用N-（苄氧基羰基）-L-谷氨酸和N-（苄氧基羰基）-L-天冬氨酸，作为胺成分，使用L-谷氨酸二乙酯和L-天冬氨酸二乙酯。本文主要研究了在30 ℃下合成N-苄氧羰基-L-谷氨酰-L-谷氨酸二乙酯（Z-GluGlu（OEt）_2）的反应。结果表明：1）合成反应不发生在缓冲溶液中; 2）在以乙酸乙酯为溶剂的水-有机两相反应体系中，Z-GluGlu（OEt）_2的产率最高可达70%左右; 3）将酶固定在各种多孔载体上，得到了较好的固定化效果。 ...更多信息运动。首先将酶吸附到载体上，然后用戊二醛交联。当酶被吸附到多孔陶瓷载体（SM 10-C1，Nippon Gaishi K. K.）。4)固定化酶的活性强烈依赖于外部有机溶剂中的水含量。当底物含水量为2.5%时，固定化酶的活性最高，而固定化酶的底物为L-谷氨酸二乙酯，底物中的一种胺组分被非酶促转化为L-焦谷氨酸二乙酯。提高固定化酶的浓度对降低非酶反应的影响最为有效。在100 mM Z-Glu和200 mM Glu（OEt）_2，固定化酶浓度为8%的条件下，产率达到90%以上。6）在与（5）相同的反应条件下，也以相当高的产率获得了另外三种二肽前体。少