Biological buffer is a kind of solution that can keep the pH value of the solution relatively stable when adding a small amount of acid / base. The pH range of biological buffer was determined by its pKa value. The pKa value is defined as the pH value when 50% of the molecules are of acid structure and 50% of the molecules are of basic structure. A general principle of biological buffer is that its pH value should be within one pH unit of pKa value, so as to ensure its good buffer capacity. This can ensure that there are enough molecules with acid structure and basic structure at the same time, which can be neutralized when H + or Oh - is added. In this way, the buffer can prevent the change of protein stability caused by the change of pH.
Many substances can be used in biological buffers. The commonly used buffer components usually have a nearly neutral pKa value and can be used in the physiological pH range. The following is a list of the three most commonly used biological buffers, their respective pH application ranges, and their respective advantages and disadvantages that may affect the protein purification process. In order to ensure sufficient buffer capacity, the concentration of these buffers is usually 25 mm.
Mops buffer: pH range of 6.5-7.9, can not be autoclaved, pH value changes with temperature to a certain extent, and has high buffer capacity in physiological pH range.
HEPES buffer: pH range is 6.8-8.2, can not be autoclaved, pH value changes with temperature to a certain extent, free radicals will be generated under certain conditions.
Tris buffer: pH range is 7.5-9.0, pH value changes with temperature or dilution degree to a certain extent, which will affect the activity of some enzymes. It has no UV absorption and is cheap.
The function of buffer solution is to adjust the pH value of the solution in a limited range, so that the acidity of the solution to be determined can meet the range specified by the analytical method. For example, phenol can react with 4-aminoantipyrine in alkaline medium and in the presence of potassium ferricyanide to form orange red antipyrine dye. In order to prevent the interference of aromatic amines, the optimum pH is 10 ± 0.2. For this reason, it is necessary to add ammonia chloride buffer solution to the solution to be tested, and adjust and control the pH of the solution to be tested to 10.0 ± 0.2.
Hubei xindesheng Materials Co., Ltd. specializes in the production and research of biological buffer and blood collection additive, enzyme preparation, chemiluminescent reagent and luminescent substrate. Desheng has been established for decades, has its own R & D team, and has researched and developed biological buffers for many years. Its products include Tris, HEPES, taps, mops, caps, bicine, EPPs, pipes and a series of biological buffers. At present, the products produced by Desheng have been sold to many countries all over the world, all of which have received high praise and re purchase, and have reached long-term cooperation with many enterprises. Interested in understanding can call consultation, Desheng welcome your call.
