亮-脑啡肽基因的合成

本文报道亮-脑啡肤基因的另一个合成途径。合成的基因,26个碱基对,是按照亮-脑啡肽的氨基酸顺序设计的。为了能够插入pBR 322质粒,基因带有EcoRI和BamHI限制性内切酶的单链粘性末端。化学合成的4个片段,8、9、17及18核苷酸,采用改良的三酯法。这些片段都具有正确的结构,最后在T_4-DNA连接酶的作用下,一步装配成脑啡肽基因。产物用聚丙烯酰胺凝胶电泳纯化,具有正确的连接点。     

SYNTHESIS OF THE LEU-ENKEPHALIN GENE

The synthesis of Leu-enkephalin gene by an alternative approach was described in thispaper. The sequence of the synthetic gene, 26 base-pairs in length, was derived from the ami-no acid sequence of the hormone peptide Leu-enkephalin. It bears single-stranded cohesive ter-mini for the restriction endonucleases EcoR I and BamH I so that it may be inserted into apBR 322 plasmid. The 4 deoxyoligonucleotide fragments, varying in length from octanucleotideto octadecanucleotide, were synthesized by an improved phosphotriester method developed inour laboratory. All chemically synthetic fragments were pure and had the correct sequences.The assembly of the Leu-enkephalin gene was carried out in a one-step ligation reaction cata-lysed by T_4-DNA ligase with good yield, Finally, the purified products from polyacrylamidegel electrophoresis had the correct joining-points as predicted.     

N9位芳基取代嘌呤-8-酮类衍生物的合成及抗肿瘤活性

合成了一系列N9位芳基取代嘌呤-8-酮类衍生物, 利用核磁共振氢谱(¹H NMR)、 核磁共振碳谱(¹³C NMR)和高分辨质谱(HRMS)进行了结构确证. 采用四甲基偶氮唑盐(MTT)法测定了目标化合物的体外抗肿瘤细胞增殖活性. 结果表明, 嘌呤酮环的C2位及N9位的取代对活性有较大影响, C2位引入对位由含氮六元环取代的苯胺, N9位引入对三氟甲基苯均有利于提高抗肿瘤活性. 化合物12c对人白血病细胞(K562)、 人前列腺癌细胞(PC-3)、 人乳腺癌细胞(MDA-MB-231)及人结肠癌细胞(HCT116)的抑制效果明显优于阳性对照药R-Roscovitine.