Fluorescent staining of glycoproteins in sodium dodecyl sulfate polyacrylamide gels by 4H--benzopyrano[4,3-b]thiophene-2-carboxylic acid hydrazide†
A fluorescent detection method for glycoproteins in SDS-PAGE by using 4H--benzopyrano[4,3-b]thiophene-2-carboxylic acid hydrazide (BH) was developed in this study. As low as 4–8 ng glycoproteins (transferrin, α1-acid glycoprotein) could be specifically detected by the BH staining method, which is twofold more sensitive than that of the most commonly used Pro-Q Emerald 488 glycoprotein stain. Furthermore, the specificity of the newly developed stain for glycoproteins was demonstrated by 1-D and 2-D SDS-PAGE, deglycosylation, glycoprotein affinity enrichment and LC-MS/MS, respectively. According to the results, it is concluded that BH stain may provide new choices for convenient, sensitive, specific and economic visualization of gel-separated glycoproteins.