Kurien Biji T, Dorri Yaser, Scofield R Hal
Department of Veterans Affairs, University of Oklahoma Health Sciences Center, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.
Methods Mol Biol. 2012;869:567-78. doi: 10.1007/978-1-61779-821-4_51.
Gel proteins are commonly stained with calorimetric/fluorescent dyes. Here, we demonstrate that heat-solubilized curcumin can serve as a nontoxic and environment-friendly fluorescent/colorimetric reversible protein stain. Curcumin, the yellow pigment found in the rhizomes of the perennial herb Curcuma longa (turmeric), is insoluble in aqueous solvents. However, heat (100°C) solubilization in water renders 1.5% of curcumin soluble. Curcumin solubilized by ethanol or alkali is ineffective in staining proteins. Heat solubilized curry spice turmeric stains proteins similarly. Staining is achieved in 30 min, with a sensitivity almost equaling that of Coomassie Brilliant Blue (CBB). Destaining is not required, and excess curcumin/turmeric can be discarded into the sink. Binding of proteins by silver inhibits curcumin binding, suggesting similarity of protein binding by silver and curcumin. It costs $1.5-2.0 to stain a mini-gel with curcumin, while turmeric costs less than 0.005 cent. CBB staining/destaining costs about 2 cents. However, CBB is toxic and its use necessitates specialized disposal efforts. Curcumin/turmeric, thus, can serve as an ideal nontoxic protein stain.
凝胶蛋白通常用比色/荧光染料染色。在此，我们证明热溶解的姜黄素可作为一种无毒且环保的荧光/比色可逆蛋白染色剂。姜黄素是多年生草本植物姜黄根茎中的黄色色素，不溶于水性溶剂。然而，在水中加热（100°C）溶解可使1.5%的姜黄素溶解。用乙醇或碱溶解的姜黄素对蛋白质染色无效。热溶解的咖喱香料姜黄对蛋白质的染色效果类似。30分钟内即可完成染色，灵敏度几乎与考马斯亮蓝（CBB）相当。无需脱色，多余的姜黄素/姜黄可倒入水槽。银与蛋白质的结合会抑制姜黄素的结合，这表明银和姜黄素与蛋白质的结合具有相似性。用姜黄素染色一块迷你凝胶的成本为1.5 - 2.0美元，而姜黄的成本不到0.005美分。CBB染色/脱色成本约为2美分。然而，CBB有毒，使用时需要专门的处理措施。因此，姜黄素/姜黄可作为一种理想的无毒蛋白染色剂。
