从我国东北槲寄生(Viscum coloratum (Kom．)Nakai)中分离鉴定了5种多肽,其中,3种是新成分,命名为槲寄生毒素B5、B7、B8,B7是目前分离鉴定的唯一含有四对二硫键的槲寄生毒素;1 种鉴定为槲寄生毒素C1,系首次从我国槲寄生中分得;还有一种命名为B4,与已知的B6的一级结构相同,但HPLC保留时间相差很大,应该是一个新肽。它们的一级结构分别为:B5 KSCCPSTTGR NIYNTCRFTG SSRETCAKLS GCKIISASTC PSDYPK:B8 KSCCPSTTGR NIYNACRFTG SSRETCAKLS GCKIISASTC PSDYPK;B7 KSCCRNTTGRN CYNTCRLPG TPRPVCASLC DCKIISGSKC PADYPR:C1 KSCCPNTTGR NIYNTCRFAG GSRERCAKLS GCKIISASTC PSDYP K;B4 KSCCPNTTGR NIYNTCRFAG ASRERCAKLS GCKIISASTC PSDYPK。它们对不同肿瘤细胞系具有选择性细胞毒活性,槲寄生总肽对于人肺癌细胞A549、人宫颈癌细...更多胞Hela、人脑瘤细胞SF126的IC50值分别为:3．7、1．5、2．1μg／mL;B4 分别为1．3、1．3、1．6μg／mL;B7分别为:12、1．3、6．0μg／mL。而对于人胃癌细胞BGC效果不明显。

Five polypeptides have been isolated from Viscum coloratum (Kom.Nakai)growing in the Northeast China,of which three are newly found and named visotoxin B5,B7 and B8. B7 is the only viscotoxin which has 4 disulphide bonds according to the identification made so far.One viscotoxin is confirmed as viscotoxin C1 obtained first from Viscum coloratum in China and the other one is named B4,whose structure is the same to the primary structure of the already known B6,but whose retention time is greatly different from that of B6 by HPLC,and therefore it must be a new polypeptide.The following is the primary structure of the polypeptides involved: KSCCPSTTGR NIYNTCRFTG SSRETCAKLS GCKIISASTC PSDYPK ofB5,KSCCPSTTGE NIYNACRFTG SSRETCAKLS GCKIISASTC PSDYPK ofB8,KSC-CRNTTGRN CYNTCRLPG TPRPVCASLC DCKIISGSKC PADYPR ofB7,KSCCPNTTGR NIYNTCRFAG GSR-ERCAKLS GCKIISASTC PSDYPK of Cl and KSCCPNTTGR NIYNTCRFAG ASRERCAKLS GCKIISASTC PSDYPR of B4.ALL the polypeptides mentioned above possess selective cytotoxic ac...更多tivity for different cancer clones.The IC50 values of the total polypeptides of Viscum coloratum in the lung cancer cell A549,the cervical carcinoma cell Hela and the cerebral cancer cell SF126 of human beings are 3.7μg/mL,1.5μg/mL and 2.1μg/mL.respectively.The IC50 Values of B4 in the cells as metioned above are 1.3μg/mL,1.3μg/mL and 1.6μg/mL and those of B7 are 1.2μg/mL,13μg/mL and 6.0μg/mL respectively.Nevertheless,their result is not clear in the gastric cancer cell BGC of human beings.