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Updated: Oct 19, 2026
Staining Proteins in Gels
Published on: July 8, 2008
Visualization of the enzyme trimethylamine oxide demethylase in isoelectric focusing gels by an enzyme-specific
W Havemeister1, H Rehbein, H Steinhart
1Federal Research Center for Fisheries, Institute of Biochemistry and Technology, Hamburg, Germany.
Abstract:
An enzyme-specific staining method for trimethylamine oxide demethylase (TMAO-ase) was developed. Direct visualization could be reached by coupling the reactions of the specific TMAO-ase assay with another reaction step generating as final product a dark-blue formazan. For these purposes 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) as tetrazolium salt and phenazine methosulfate (PMS) as electron transfer substance were used. Clear, dark-blue colored bands could be detected on 300 microm isoelectric focusing gels (IEF). Comparisons of enzyme-stained and protein-stained gels showed that diffusion could not be observed and that the band pattern of TMAO-ase could also be seen in the protein stain. The pI range where TMAO-ase was located was 5.6-6.6 for extracts and 6.2-6.6 for partially purified TMAO-ase. Specificity of stained TMAO-ase bands was assessed by the preparation of staining solution without the substrate trimethylamine oxide (TMAO) and by extraction of TMAO-ase from the gel and performance of the specific TMAO-ase assay.
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