When we use Good's buffer, we always inadvertently confuse HEPES and PIPES in Good's buffer, thinking that they are the same, which makes it impossible to distinguish accurately. In fact, there are similarities between them, but there are also many different characteristics. Especially during our experiment, a slight difference may lead to failure in the experiment. So we have to be clear about what is a buffer and what does it do? In order to distinguish between HEPES and PIPES in the buffer, where is the difference? What should we pay attention to when using?

Buffer solution is a type of buffer system dedicated to life science research. in biochemical experiments, buffer solution plays an indispensable role. It can resist the influence of a small amount of strong acid and alkali from the outside, and maintain the system closest to the physiological environment. PH value. both HEPES and PIPES buffers are commonly used buffers in biological experiments.

Desheng biological buffer packaging picture

the pH buffer range of HEPES is 6.8-8.2. It is a zwitterionic biological buffer. It is soluble in water and does not form stable complexes with metal ions. in most cases, it will not interfere with biochemical processes and can be widely used in a variety of Biochemical reactions and used as buffer reagents in certain cell culture media. HEPES is often used in the cell culture medium of various types of organisms; in protein research, PIPES is often used as the component and eluent of the binding buffer in cation exchange chromatography; in DNA research, PIPES is used as calcium phosphate and DNA the buffer for the precipitation formation system, AFM and the buffer for electroporation experiments. In addition, HEPES interferes with the reaction between DNA and restriction enzymes, and is not suitable for Lowry's method to determine protein content. HEPES buffer is often used in the research of organelles and highly variable, pH-sensitive proteins and enzymes, as well as in biochemical diagnostic kits, DNA/RNA extraction kits and PCR diagnostic kits. It is a hydrogen ion buffer that can control a constant pH range for a long time. the final concentration is 10-50mmol/L, and the buffering capacity can be achieved when the culture medium contains 20mmol/L HEPES.

the pH buffer range of PIPES is 6.1-7.5, insoluble in water, soluble in NaOH aqueous solution. PIPES is different from buffers containing two (2-hydroxyethyl) amino groups (such as Bis-tris, Bicine), and can not form stable complexes with most metal ions. It is suitable for buffers in solution systems containing metal ions. According to existing research results, PIPES can be used to purify tubulin using phosphocellulose chromatography, to purify recombinant GTP-binding proteins ARF1 and ARF2 by gel filtration, and to use as a buffer to crystallize transketolase from E. coli. In addition, because PIPES can form free radicals, it is not suitable for redox systems. In cation exchange chromatography, a low concentration of PIPES buffer should be used, because PIPES has a relatively large ionic strength and its pKa value is concentration-dependent.

It can be seen from the above that neither PIPES nor HEPES can form stable complexes with metal ions and are suitable for solution systems containing metal ions. but there are also certain differences between them. In terms of solubility, PIPES is insoluble in water, while HEPES has good water solubility; in terms of buffer range, PIPES is acidic to neutral, and HEPES is neutral to alkaline. this is mainly Due to the structural difference between the two, PIPES has two sulfonic acid groups, and HEPES contains one sulfonic acid group and a hydroxyl group. In addition, PIPES and HEPES have certain restrictions in certain system applications. Therefore, when we choose the above-mentioned buffer, we need to consider the suitability of the experimental system and the difference in the properties of the two.

We must learn to distinguish between the similarities and differences in these reagents, so as to better promote the development and production of our different products. Desheng unanimously adheres to this kind of subtle difference, so that it can continue to develop and produce better products.