工程菌产黑色素的抗氧化作用研究

Studies on the Anti-Oxidation Behavior of Melanin from Engineering Bacteria

利用黑色素对苯甲酸羟基化产物荧光强度的猝灭作用,研究了重组的苏云金芽孢杆菌(Bacillusthuringiensis)pHTAM菌株产生的黑色素对羟自由基的清除作用,发现其具有与Sigma标准黑色素相当的清除羟基自由基的能力,且优于生物提取的国产商品黑色素;与硫脲等其它常见的抗氧化剂比较,该工程菌产黑色素清除羟自由基的效果明显,尤其是在低剂量时这种优势更为突出.通过动力学研究证实其对羟自由基的清除作用是基于氧化还原反应而非吸附作用.

The anti-oxidation behavior of melanin was studied through detecting its hydroxyl radicals scavenging activity, which was produced by genetic engineering microbe (GEM) Bacillus thuringiensis/pHTAM. It was found that the GEM-produced melanin possessed a higher scavenging ability towards hydroxyl radicals as compared with some currently commercial melanin. The scavenging activity of GEM-produced melanin was also higher than some normally seen antioxidants such as uric acid, especially at quite low concentrations. Kinetic studies showed that the scavenging activity came from the redox reaction between melanin and hydroxyl but not the adsorption of radicals as reported by literatures.