Just like other biological systems, the human body relies on biological buffers to maintain the ideal pH balance. Without them, we wouldn’t be able to maintain homeostasis or perform vital biological functions.
Our blood, for instance, requires a pH range of between 7.35 and 7.45. If it becomes too alkaline it can lead to a condition known as alkalosis, which may cause tremors, muscle spasms, nausea, seizures, and even death. Similar symptoms can also occur if our blood becomes too acidic (a condition called metabolic acidosis).
To help our bodies function normally, the pH of blood is maintained by a buffer system. In this case, the carbonic acid (H2CO3) and bicarbonate anion (HCO3−) present in blood serve as the pH buffers that are responsible for maintaining the optimal pH range.
However, biological buffers don’t just play an essential role in the human body. Other biological systems, whether in a petri dish or an entire forest ecosystem, also have their own corresponding buffers. And, as we explain below, they’re a vital part of many industrial manufacturing processes too.
In this post:
What are the most important biological buffers?
There are several biological buffers that maintain homeostasis and a stable pH in biological systems. However, the four most important buffers in living organisms are the:
- Bicarbonate buffer
- Phosphate buffer
- Protein buffer
- Haemoglobin buffer
The bicarbonate buffer ensures human blood stays within its optimal pH range. It’s composed of carbonic acid and bicarbonate ions. When the blood pH becomes acidic, the buffer forms carbon dioxide gas. This gas is then expelled out of the body during the respiration process. On the other hand, if the blood becomes too alkaline, bicarbonate ions are excreted by the kidneys through urination.
Similar to the bicarbonate buffer, the phosphate buffer is composed of hydrogen phosphate ions and dihydrogen phosphate ions. This buffer system is present in all cell fluid. When excess hydrogen ions or protons enter the cells, the hydrogen phosphate ions maintain the optimal pH balance by reducing the acidity level. Conversely, the dihydrogen phosphate ions reduce alkalinity by accepting excess hydroxide ions.
All proteins are composed of amino acids as building blocks. These amino acids form chains that are held together by peptide bonds. Each amino acid has a carboxylic functional group and an amino group. The carboxyl group accepts excess protons under acidic conditions. If the system becomes too alkaline, protons are released from the amino group.
Why are buffers important for protein function?
Many proteins in living organisms act as enzymes that facilitate biochemical reactions, including protein synthesis. However, their composition and peptide bonds mean proteins are sensitive to pH changes.
Complex proteins can even lose their molecular integrity if they’re subjected to a pH beyond their optimal range. Buffers therefore play a crucial role in protein function as they help to regulate any potentially damaging shifts in pH.
The most common types of biological buffers used in chemical manufacturing
As well as helping to maintain homeostasis in living organisms, biological buffers play an important role in many industrial processes. They’re particularly useful in food and drink manufacturing, for instance. Chemical manufacturers like ReAgent also supply biological buffers for use in a range of medical devices and test kits.
Some of the most common types of biological buffers used in industry are summarised below.
1. Bicarbonate buffer
As we explained earlier, the bicarbonate buffer is primarily responsible for maintaining our blood pH level. It’s composed of carbonic acid and carbonate anions that are in dynamic equilibrium, as shown in the chemical equation below.
However, this buffer system is also commonly used to prepare carbonated beverages and ammonium salts, such as ammonium persulfate.
2. Phosphate buffer
A phosphate buffer system is composed of hydrogen phosphate ions and dihydrogen phosphate ions. Phosphate buffers are often used in the food industry to test for bacteria and as a buffer for food products. They’re also used as an emulsifier and anti-caking additive.
3. Citrate buffer
Prepared from citric acid, a citrate buffer has a pH range of between 3.0 and 6.2. The acid itself is used as a food additive, especially in the manufacture of fruit-flavoured beverages.
A citrate buffer system also has a role in RNA isolation due to its ability to prevent base hydrolysis. In some cases, citrate buffer solutions may be used to detect certain antigens.
4. Tris buffer
Chemically known as Tris (hydroxymethyl) aminomethane, Tris is a crystalline powder at room temperature. It can inhibit and react with several types of enzymes. A Tris buffer plays a role in many biological experiments, as well as DNA extraction and DNA electrophoresis analysis. It’s also commonly used to test various pharmaceutical products.
The impact of pH on enzyme activity & how biological buffers can stabilise enzyme activity
The main role of biological buffers is to stabilise the pH in biological systems and thereby ensure enzymes can function effectively. Enzymes are susceptible to denaturation or changes in their protein structure when they’re subjected to pH levels beyond the optimal range.
In living organisms, buffers help to maintain homeostasis by stabilising enzyme activities. The substrate structure of enzymes is crucial to their effectiveness. This structure is dependent on the protein molecular arrangement (tertiary structure) or folds. Buffers prevent the enzymes from losing their optimal structures through the denaturation process.
Conversely, biological buffers can be used in experiments like DNA electrophoresis to actively prevent or inhibit enzymes from performing their usual functions. In some cases, the buffers react with enzymes and direct them to perform specific functions intended by the experimenter.
There are several different biological buffers that help maintain homeostasis in organisms and biological systems. Their main role is to keep a stable pH range so that certain metabolic and enzymatic activities can occur. The same biological buffers can also be used in biological experiments and industrial manufacturing processes.