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KUMASI™ KUMASI™ stabilized colloidal stain for polyacrylamide gels The Coomassie Chronicles The Coomassie dyes, named in commemoration of the British occupation of the Ashanti capital Kumasi in Ghana, have remained in use for over 50 years. Faseka de St. Groth et al [1] first described the use of Coomassie Brilliant Blue (CBB) for staining proteins separated on cellulose acetate membranes and demonstrated its strict adherence to Beer’s law. Soon afterwards, CBB would be popularized for staining proteins in polyacrylamide gels [2,3]. Members of the first Electrophoresis Societies became known as the “Bluefingers” and some German practitioners were mistaken for counterfeitors for the residual blue stain always on their hands. Comparison of CBB to silver staining Silver stain is inarguably the most sensitive stain. It is mimics a photographic process in which the latent image is “developed” by the reduction of silver ions. However, since the binding of silver ions to proteins is highly dependent on amino acid composition, all proteins are not stained equally and some are poorly stained or not stained at all. There is a low correlation between silver staining and CBB, where r = 0.657. KUMASI stabilized colloidal Coomassie stained two-dimensional gels with greater sensitivity than the SYPRO Ruby and Deep Purple fluorescent stains. KUMASI stabilized colloidal stain can be reused at least four times, reducing waste streams by 75% or more. Comparison of KUMASI to fluorescent dyes KUMASI stabilized colloidal Coomassie stained twodimensional gels with greater sensitivity than the SYPRO Ruby and Deep Purple fluorescent stains (Figure 1). Further, the photoinstability of these stains has been reported [6]. Deep Purple fluorescence decreases nearly 30% after only two minutes of UV transillumination. The correlation between SYPRO Ruby and KUMASI is r = 0.825. Neuhoff et al. [4] and Candiano et al. [5] exploited the colloidal properties of the dimethylated form of CBB and achieved sensitivity similar to silver staining. Figure 1. Relative sensitivity of KUMASI (left), SYPRO Ruby (center) and Deep Purple stains. Mean number of protein spots detected in triplicate gels is reported (lower left). Insets show differential staining of proteins. References 1. Fazekas De St. Groth S, Webster RG, Datyner A. (1963). Biochim. Biophys. Acta. 71, 377-385. 2. Meyer TS, Lambert BL (1965). Biochim. Biophys. Acta. 107, 144-145. 3. Altschul, A. M.; Evans, W. J. (1967). Methods in Enzymology 11, 179–186. 4. Neuhoff V, Stamm R, Eibl H. (1985). Electrophoresis, 6, 427-448. 5. Candiano G, Bruschi M, Musante L, Santucci L, Ghiggeri GM, Carnemolla B, Orecchia P, Zardi L, Righetti PG. Electrophoresis 25, 1327-1333. 6. Smejkal GB, Robinson MH, Lazarev A. (2004). Electrophoresis 25, 2511-2519. Comparison to competing Coomassie Dyes KUMASI stabilized colloidal stain detected 28% more protein spots in two-dimensional gels of Escherichia coli lysate than Thermo-Pierce GelCode Blue Stain (Figure 2). Reducing your Coomassie footprint Compared to conventional Coomassie stains which generate chemically hazardous waste streams, the new generation of “ecologically friendly” Coomassie stains exhibit significantly decreased sensitivity. The solution is the KUMASI stabilized colloidal stain which can be reused at least four times, reducing waste streams by 75% or more. The KUMASI Fixative and Enhancer solutions can also be reused and are compatible with sink disposable. Figure 2. Identical 2D gels of Escherichia coli lysate stained with KUMASI (left) or GelCode Blue (right). The mean number of total protein spots detected in duplicate gels is reported (upper right). KUMASI detected 219 proteins not detected by GelCode Blue. Focus Proteomics is a proteomics CRO specializing in protein fractionation, two-dimensional gel electrophoresis (2DGE), and label-free quantitative mass spectrometry (LFQMS) to identify and quantify proteins and their posttranslational modifications. Contact: Phone: Email: Focus Proteomics, LLC 32 Overlook Circle Hudson, NH 03051 (603) 204-4947 [email protected] www.focusproteomics.com