Protein determination by ponceau S using digital color image analysis of protein spots on nitrocellulose membranes.

Abstract

A procedure was developed to estimate protein concentrations using color image analysis of protein spots stained with ponceau S. The method involved spotting a constant volume (2 microl) of the protein solutions on nitrocellulose paper, staining with acidic ponceau S, destaining, and air drying the paper. The image of the nitrocellulose paper was grabbed using a digital color scanner and thresholded with an optimal value to mark the area of the spot. The intensity of the color in the spot was measured in an arbitrary unit of intensity termed as inverse integrated gray value. This value showed a discernible increase with protein concentrations from 0.1 to 50 microg protein per spot (0.05-25 mg/ml). The method is simple and convenient compared to the conventional spectrophotometric procedures and allows several samples to be analyzed simultaneously. It can also be used to estimate protein concentration in the spots stained with Coomassie brilliant blue or other dyes.

• Authors: S V Bannur, S V Kulgod, S S Metkar, S K Mahajan, J K Sainis
• Journal: Analytical biochemistry (Anal Biochem) Vol. 267 Issue 2 Pg. 382-9 (Feb 15 1999) ISSN: 0003-2697 [Print] United States
• PMID: 10036145 (Publication Type: Journal Article)
• Copyright: Copyright 1999 Academic Press.

Chemical References

• Proteins
• Collodion

Topics

• Collodion
• Color
• Image Processing, Computer-Assisted
• Proteins (analysis)