Overview: Good's Buffers
Developed in the mid-1960s, Dr. Norman E. Good, an American biochemist, developed a series of biological buffers ideal for a variety of experiments for the biological sciences [1]. These buffers were named after him and are now known as Good’s buffers. Composed of 20 different zwitterionic compounds, Good’s buffers are known to be some of the most suitable buffers in biochemistry, as they possess the following qualities:
- Have pKa (negative logarithm of acid dissociation constant) values between 6.0 and 8.0.
- Have high water solubility and low solubility in organic solvents.
- Low cell membrane permeability.
- Consistent acid-base dissociation constants.
- Low metal chelating capability
- Have minimal salt effects.
- Have minimal effects on dissociation from changes in temperature and concentration.
- Have well-behaved cation interactions.
- Are chemically stable, resisting enzymatic and non-enzymatic degradation.
- Are biochemically inert, meaning that they should not influence or participate in any biological reactions.
- Have low optical absorbance either in the visible or in the UV region
Upon formulation of Good’s buffers, scientists can expect desirable buffering performances in maintaining the correct osmotic pressure, pH, and environmental conditions for a vast array of reactions. From real-time polymerase chain reaction (RT-PCR) analysis, to electrophoresis, chromatography, protein crystallization, cell culture, and biologics manufacturing, Good’s buffers are some of the most application-flexible compounds in biochemistry.
What is a Zwitterionic Compound?
Zwitterionic compounds are essential components of Good’s buffers and are neutral compounds that have both positive and negative regions of charge. Although these compounds do not dissociate in polar solvents, their dipolar nature allows for them to easily dissolve in polar solvents and interact ionically and covalently. This allows for the flexible maintenance of pH in many different solution types by both donating and accepting electrons at different environmental pH values.
4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid, also known as HEPES, is a well-known zwitterionic compound that forms a Good’s buffer known as a HEPES Buffer when presented with water as a solvent. HEPES is a sulfonic acid buffering agent and contains several functional groups including sulfonic acid (pKa – 7.5), and a piperazine ring (pKa – 3). The piperazine ring in this case acts as a base, as is contains an amino group capable of accepting a proton to become positively charged in an acidic environment, whereas sulfonic acid acts as an acid, as it donates protons in the presence of a basic environment. See the molecular structure of HEPES below:
Image 1: The molecular structure of HEPES. In the far left of the image, the structure of sulfonic acid can be seen currently deprotonated, holding a slightly negative charge. Toward the center of the image, a piperazine ring can be seen holding a partially positive charge, as one of its nitrogen atoms has accepted a proton. The partially charged nature of HEPES allows it to act as a buffer in the presence of hydrogen ions.
Examples of Good’s Buffers
The chemicals used to create Good’s buffers are found in the following list. This list encapsulates many chemicals Norman Good had discovered that had met his buffer acceptance criteria. The pH ranges of buffers are directly correlated to the pKa values of their functional groups.
Buffer Name |
Functional Groups |
pH Range |
pKa Value |
|---|---|---|---|
| ACES Buffer | Contains amino (basic) and acetic acid (acidic) functional groups. | 6.1 – 7.5 | 6.88 |
| ADA Buffer | Contains amino (basic) and carboxyl (acidic) functional groups. | 6.0 – 7.2 | 6.59 |
| AMPD Buffer | Contains amino (basic) and carboxyl (acidic) functional groups | 7.8 - 9.7 | 8.5 |
| AMPSO Buffer | Contains amino (basic) and hydroxy (acidic) functional groups. | 8.3 – 9.7 | 9 |
| BES Buffer | Contains amino (basic) and hydroxyl (acidic) functional groups | 6.4 - 7.8 | 7.1 |
| Bicine Buffer | Contains amino (basic) and hydroxyl (acidic) functional groups. | 7.6 - 9.0 | 8.3 |
| Bis-Tris Buffer | Contains amino (basic) and hydroxyl (acidic) functional groups. | 5.8 - 7.2 | 6.46 |
| Bis-Tris Propane Buffer | Contains two amino (basic) and one hydroxyl (acidic) functional groups. | 6 - 9.5 | 6.8 & 9.0 |
| CABS Buffer | Contains cyclohexylamino (basic) and sulfonic acid (acidic) functional groups. | 9.7 - 11.1 | 10.4 |
| CAPS Buffer | Contains amino (basic) and sulfonic acid (acidic) functional groups | 9.5 - 11.5 | 10.4 |
| CAPSO Buffer | Contains amino (basic) and hydroxy (acidic) functional groups | 8.9 - 10.3 | 9.6 |
| CHES Buffer | Contains amino (basic) and sulfonic acid (acidic) functional groups | 8.6 - 10.0 | 9.49 |
| DIPSO Buffer | Contains amino (basic) and sulfonic acid (acidic) functional groups | 7.0 - 8.2 | 7.35 |
| Glycyl-glycine Buffer | Contains amino (basic) and carboxyl (acidic) functional groups | 7.5 - 8.9 | 8.2 |
| HEBPS Buffer | Contains amino (basic) and carboxyl (acidic) functional groups | 7.6-9.0 | 8.3 |
| HEPES Buffer | Contains amino (basic) and hydroxyl (acidic) functional groups | 6.8 - 8.2 | 7.48 |
| HEPPS (EPPS) Buffer | Contains amino (basic) and hydroxyl (acidic) functional groups | 7.3 - 8.7 | 8 |
| HEPPSO Buffer | Contains amino (basic) and hydroxyethyl (acidic) functional groups | 7.1 – 8.50 | 7.8 |
| MES Buffer | Contains amino (basic) and sulfonic acid (acidic) functional groups | 5.2 - 7.1 | 6.16 |
| MOBS Buffer | Contains morpholino (basic) and sulfonic acid (acidic) functional groups | 6.9 - 8.3 | 7.6 |
| MOPS Buffer | Contains amino (basic) and sulfonic acid (acidic) functional groups | 6.5 - 7.9 | 7.2 |
| MOPSO Buffer | Contains amino (basic) and sulfonic acid (acidic) functional groups | 6.2 - 7.6 | 6.9 |
| PIPES Buffer | Contains amino (basic) and sulfonic acid (acidic) functional groups | 6.1 - 7.5 | 6.8 |
| POPSO Buffer | Contains piperidino (basic) and hydroxyl (acidic) functional groups | 7.2 - 8.5 | 7.8 |
| TABS Buffer | Contains amino (basic) and sulfonic acid (acidic) functional groups | 8.2 - 9.6 | 8.8 |
| TAPS Buffer | Contains amino (basic) and hydroxyl (acidic) functional groups | 7.7 - 9.1 | 8.49 |
| TAPSO Buffer | Contains amino (basic) and sulfonic acid (acidic) functional groups | 7.0 - 8.2 | 7.635 |
| TES Buffer | Contains amino (basic) and hydroxyl (acidic) functional groups | 6.8 - 8.2 | 7.5 |
| Tricine Buffer | Contains amino (basic) and hydroxyl (acidic) functional groups | 7.4 - 8.8 | 8.16 |
| Tris Buffer | Contains amino (basic) and hydroxyl (acidic) functional groups | 7.0 - 9.0 | 8.5 |
Good’s Buffers at Boston BioProducts
Every Good’s Buffer is unique to the cell type used and the experimental application. Select the appropriate Good's Buffer from the catalog or design your optimal formulation with custom manufacturing options at Boston BioProducts.
Build a Custom Reagent Quickly
References:
-
- Islam, M.S., Aryasomayajula, A and Selvaganapathy, P.R., (2017). A Review on Macroscale and Microscale Cell Lysis Methods. Micromachines, 8(3), 83; https://doi.org/10.3390/mi8030083.
- Peach, M., Marsh, N., & MacPhee, D. J. (2012). Protein solubilization: attend to the choice of lysis buffer. In Methods in molecular biology (Vol. 869, pp. 35-42). Protein Solubilization: Attend to the Choice of Lysis Buffer | SpringerLink