Chiapella C, Ysern P, Riera J, Llagostera M
Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, Spain.
Mutat Res. 1995 Jun;329(1):11-8. doi: 10.1016/0027-5107(95)00015-b.
Microsomal fractions from different tissues of various plants (potato, cauliflower, aubergine, avocado pear, courgette, cucumber, banana, kiwi and strawberry) were prepared and their content of cytochrome P-450 (cyt-P450) determined. A S117 fraction from Persea americana (avocado pear) presented the highest content of cyt-P450. As a consequence of these data, we have developed and characterized this fraction as a plant metabolic activation system. The P. americana S117, used in this work, contains 0.75 +/- 0.04 mg of protein per ml, 0.788 +/- 0.078 nmol of cyt-P450 per mg of protein and has a peroxidase activity of 0.036 +/- 0.005 (nmol tetraguaiacol/micrograms protein/min). The P. americana cyt-P450 remained stable during at least 60 days, stored at -80 degrees C. This fraction activated 2-aminofluorene to a mutagenic product in S. typhimurium TA98, while it had no effect on the benzo[a]pyrene activation. The treatment of the P. americana S117 with CO, the addition of diethyldithiocarbamate (DETC) or the absence of a NADPH-generating system in the activation mix, produced a partial inhibition of the 2-aminofluorene activation. Both peroxidase activity and a cyt-P450-dependent activity are assumed to be involved in the activation of this chemical mediated by P. americana S117.
制备了来自各种植物（马铃薯、花椰菜、茄子、鳄梨、西葫芦、黄瓜、香蕉、猕猴桃和草莓）不同组织的微粒体组分，并测定了它们细胞色素P-450（cyt-P450）的含量。来自鳄梨（Persea americana）的S117组分呈现出最高的cyt-P450含量。基于这些数据，我们开发并鉴定了该组分作为一种植物代谢活化系统。本研究中使用的美洲鳄梨S117组分，每毫升含有0.75±0.04毫克蛋白质，每毫克蛋白质含有0.788±0.078纳摩尔cyt-P450，过氧化物酶活性为0.036±0.005（纳摩尔四愈创木酚/微克蛋白质/分钟）。美洲鳄梨cyt-P450在-80℃储存至少60天期间保持稳定。该组分在鼠伤寒沙门氏菌TA98中将2-氨基芴激活为诱变产物，而对苯并[a]芘的激活没有影响。用一氧化碳处理美洲鳄梨S117，在激活混合物中添加二乙基二硫代氨基甲酸盐（DETC）或不存在NADPH生成系统，会部分抑制2-氨基芴的激活。过氧化物酶活性和细胞色素P-450依赖性活性都被认为参与了由美洲鳄梨S117介导的这种化学物质的激活。
