Is Tris buffer suitable for protein detection by Folin phenol method

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The buffer range of trimethylolaminomethane Tris is about 6-8, which is suitable for most biochemical experiments, especially in the related research experiments of protein and nucleic acid; Hydroxyethyl piperazine propanesulfonic acid EPPs is also suitable for protein and nucleic acid research experiments, and the price is more expensive than Tris. So which one is suitable for protein detection experiment by Folin phenol method

Folin phenol reagent method is a common basic method for determining protein concentration, which is widely used in the field of biochemistry. In practical application, EPPs (hepps) is usually used as a buffer to detect protein content by Folin phenol method, rather than Tris buffer.

Buffer Tris and EPPS were used for protein content detection

The chromogenic principle of Folin phenol method for the determination of protein content is the same as that of biuret method (but EPPs can not be used for biuret / biuret detection). The difference is that the second reagent, Folin phenol reagent, is added to increase the chromogenic amount and improve the sensitivity of protein detection. Folin phenol method has the advantages of high sensitivity and much more sensitivity than biuret method. Of course, it also has some disadvantages, such as long time-consuming, non straight standard curve, poor specificity and many interfering substances.

All groups that interfere with biuret reaction, such as - co-nh2, - ch2-nh2, cs-nh2, Tris buffer, sucrose, ammonium sulfate and sulfhydryl compounds, can interfere with Folin phenol reaction, and have a much greater impact on the latter. In addition, phenols and citric acid also interfere with the reaction.

Folin phenol reagent is composed of two reagents. Reagent 1 consists of sodium carbonate, sodium hydroxide, copper sulfate and potassium sodium tartrate. Under alkaline conditions, the peptide bond in protein acts with potassium sodium copper tartrate solution to form purplish red complex. Reagent 2 is composed of phosphomolybdic acid, phosphotungstic acid, sulfuric acid, bromine, etc. Under alkaline conditions, the reagent is easy to be reduced by the phenol group of tyrosine in protein, showing a blue reaction, and its color is directly proportional to the protein content. This method is also suitable for the determination of tyrosine and tryptophan. The determination range of this method is 25-250 μ G protein.

To sum up, Folin phenol method has the advantages of high sensitivity, long time-consuming and interference, and Tris will also produce interference. EPPs buffer should be used. Desheng has produced both buffers, which is not better, but suitable for different experimental studies.