A rapid, sensitive, and specific method for the determination of protein in dilute solution

✍ Scribed by W. Schaffner; C. Weissmann

• Publisher: Elsevier Science
• Year: 1973
• Tongue: English
• Weight: 785 KB
• Volume: 56
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(73)90217-0

✦ Synopsis

A protein assay is described in which the sample is precipitated with trichloroacetic acid in the presence of sodium dodecylsulfate, filtered off on a Millipore membrane and stained with Amidoschwarz 10B. The proteindye complex is eluted, and its absorbance determined at 630 nm. This assay is very reproducible, insensitive to variations in assay conditions, and linear from 3 to 30 μg of protein. It can be used on samples with a concentration as low as 0.75 μg/ml. There is no interference by commonly used reagents such as Tris, thiol reagents, EDTA, urea, sucrose, and many others. The color yield for a variety of proteins was determined and found to lie within ±15% of the value for bovine serum albumin which was used as standard. Of the proteins tested only insulin, which due to its low molecular weight was incompletely retained on the membrane in the filtration step, gave a low color yield, 50% of the standard.