从ＤＮＡ结构损伤探讨了血卟啉衍生物（ＨＰＤ）光动力作用杀伤细胞的机理。ＤＮＡ经ＨＰＤ＋光处理后，立即进行电泳未见断链发生，但经在碱性溶液中加热处理后出现降解。这是由于碱基基团发生变化所致。引物延伸反应表明ＤＮＡ分子发生聚合。序列测定也出现错误序列，４种碱基Ａ、Ｇ、Ｃ、Ｔ均可出现改变。以小鼠艾氏腹水癌ＤＮＡ为材料，经ＨＰＤ＋光处理后再分别用ＢｇｌⅡ与ＢａｍＨⅠ降解，得到的片段比对照组变长。上述结果均说明ＨＰＤ光动力作用可使ＤＮＡ碱基发生突变。 The mechanism of photodynamic effect of hematoporphyrin derivative (HPD) on killing cells was explored from DNA damage. After the DNA was treated by HPD + light, no chain scission occurred immediately after electrophoresis, but degradation occurred after heat treatment in alkaline solution. This is due to changes in base groups. Primer extension reaction indicates that the DNA molecule is polymerized. Sequence determination also appeared wrong sequence, 4 bases A, G, C, T can be changed. The mouse Ehrlich ascites carcinoma DNA was treated with HPD + light and then degraded with BglII and BamHl, respectively. The obtained fragments grew longer than the control group. The above results indicate that the photodynamic action of HPD can make DNA base mutation.