蟾蜍毒素通常是甾体配基的3-位羟基与辛二酰基精氨酸酯侧链结合。近来发现几种带有新侧链的毒素,如代替辛二酰基的有丁二酰基,己二酞基和庚二酰基等。这几种酰基通常又与精氨酸结合。本文报道另一种新型的毒素,其侧链是辛二酰基-L-谷酰胺,而不是精氨酸,这种带有L-谷酰胺基的蟾蜍毒素,在自然界还是首次发现。分离方法:10只美洲蟾蜍(Bufo americanus)以干冰冷冻后剥皮,并立即用乙醇提取,顺次经硅胶柱层,制备薄层和萄萄糖凝胶LH-20分离纯化,得到5毫克新蟾蜍毒素(Ⅱ),熔点166～170°(分解),[α]_D~(20)+15.1°,无 Toad toxins are usually the 3-position hydroxyl group of the steroid ligand bound to suberoylaminate side chains. Recently several toxins with new side chains have been found, such as succinyl, adipyl, pimeloyl and the like in place of suberoylamino. These acyl groups are usually combined with arginine. This article reports another novel toxin, whose side chain is suberoylaminyl-L-glutamine instead of arginine. This toad toxin with L-glutamyl group was first found in nature. Isolation method: Ten Bufo americanus were frozen in dry ice and peeled off and immediately extracted with ethanol. The layers were sequentially purified by silica gel column chromatography and dextrose gel LH-20 to give 5 mg of new toad Toxin (Ⅱ), melting point 166-170 ° (decomposition), [α] D 20 + 15.1 °, none