A comparative study of different dyes for the detection of proteomes derived from Escherichia coli and MDCK cells: Sensitivity and selectivity

We compared sensitivity and selectivity of five dyes for detection of 2D PAGE-resolved proteins derived from Escherichia coli and MDCK cells. The sensitivity of these dyes was in the following order: SYPRO Ruby > Deep Purple > CBB-G250 > CBB-R250 > Colloidal Gold. Also, we report herein for the first time the application of Colloidal Gold (which is commonly used for staining proteins on blotted membranes) for in-gel staining of proteins. For E. coli, most of the dyes preferably detected proteins with pI range of 4.0–6.9, whereas Deep Purple preferably detected proteins with less acidic range (pI 5.0–7.9). For MDCK cells, while other dyes preferably stained proteins at pI range of 5.0–7.9, Colloidal Gold preferably stained more basic proteins (pI 7.0–9.9). This preferential staining property of Colloidal Gold to basic proteins was confirmed in SDS-PAGE-separated lysozyme (pI 9.4), compared to calmodulin (pI 4.0) and albumin (pI 6.0). These data provide useful information to select appropriate dyes for gel-based proteomic analysis of individual samples.