KUMASI™ stabilized colloidal stainThe Coomassie dyes, named in commemoration of the British occupation of the Ashanti capital Kumasi in Ghana, have been used as protein dyes for over 50 years. Faseka de Saint Groth et al. [1] first described the use of Coomassie Brilliant Blue (CBB) for staining proteins in cellulose acetate membranes and demonstrated its strict adherence to Beer’s law. Soon afterwards, CBB would be popularized for staining proteins in polyacrylamide and agarose 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.
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Figure 1. Comparison of KUMASI (CBB) with SYPRO Ruby and Deep Purple fluorescent gel stains.
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Comparison of KUMASI to fluorescent dyesKUMASI stabilized colloidal Coomassie stained two-dimensional 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.
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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).
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Figure 2. Duplicate 2D gels comparing KUMASI and GelCode Blue sensitivity.
Comparison of CBB to silver stainingSilver 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. 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.
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Reducing your Coomassie footprintConventional Coomassie stains generate chemically hazardous waste streams, whereas 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.
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