Cell lysis buffers are used to break down bacterial, yeast, plant or animal cells to extract proteins, DNA, RNA or organelles. Not only do cell lysis buffers lyse cells, but lysis buffers also help maintain pH, degrade contaminating components and preserve your target molecules.
Examples of when cell lysis buffers are necessary would be if you want to lyse the bacterial cells of your cloning strainto extract the recombinant DNA you have cloned for downstream steps.
Or, R&D and production labs of a biotech company might want to extract the final therapeutic recombinant protein from an expression cell culture they’ve established.
Further, diagnostic medical tests also involve lysing cells and tissues from the clinical sample to get DNA, for example, for genetic analyses.
In each of these examples, lysing the cells is just one step. But after the cells are lysed, the lysed mix exposes your target molecules to all sorts of conditions you need to control. And this is where the right cell lysis buffer becomes so useful. In addition to helping break open the cells, these buffers also maintain pH, preserve your molecules and degrade harmful molecules. Picking a cell lysis buffer becomes critical for successful extraction.
Article Table of Contents:
Degrading cell components other than the one you want to extract:
Preserving your target molecules during cell lysis:
pH maintenance:
Biomolecules that you would want to extract by lysing cells, proteins and nucleic acids are extremely finicky about pH. And cell lysis buffers ensure that the optimal pH required for the target biomolecule is maintained during the experiment.
Buffers, in general, have a lot to do with maintaining the pH required in experiments, and the chemistry behind how buffers help maintain a tight pH range is complicated. You can get an easy grasp of this concept here.
Breaking open the cells:
Another important role cell lysis buffers play is breaking open your cells. All cells have cell membranes. Additionally, some cells also have a cell-wall.
This would mean you might have to break open both cell-walls and cell membranes to extract your target molecules.
Cell lysis buffers have two types of chemicals that are very helpful with this. The first are detergents that act on the cell membranes. The second are enzymes such as lysozyme or zymolase that act on cell walls.
You first select a buffer that maintains the pH that you require for your lysis procedure. And then, these chemicals – detergents, lysozyme etc. are added to this buffer to make it suitable for lysing your target cells or tissues.
Degrading cell components other than the one you want to extract:
Suppose you are extracting DNA, the lysis buffer you would use would have proteases and RNases to degrade proteins and RNAs respectively so that you end up extracting DNA that does not have protein or RNA contamination.
On the other hand, if you are lysing the cells to extract a protein, your lysis buffer would contain DNases and RNases.
These exogenously or externally enzymes are another important component in cell lysis buffers enabling them to perform their role in cell lysis. Similar to chemicals like detergents that help with lysis, these enzymes are also added to the buffer for the purpose of making it efficient in lysis.
Preserving your target molecules during cell lysis:
The molecules that you want to extract might be prone to degradation during the cell lysis procedure.
For example, you might be lysing your cells to extract a specific protein or the transcriptome, and proteases and RNases might ruin your extraction. These proteases and RNases might be native, that is, the cell’s own enzymes; or, they can also contaminate from an outside – maybe from the benchtop or pipette tips or microcentrifuge tubes etc.
So, depending on what you are extracting – proteins or RNA, you would want to have protease inhibitors or RNase inhibitors in your cell lysis buffer.
We have a helpful article about proteases that goes into more detail if you are interested in a refresh.
Another example where preserving your target is necessary is if you are extracting proteins in their phosphorylated forms. In this case, your cell lysis buffer would need phosphatase inhibitors.
To learn more about phosphatase inhibitors, how they function and why they are important in experiments, here is a great article to read.
In addition to what we covered here, the lysis buffers commonly have some other chemicals like salts, for example, used to maintain ionic balance and optimal osmolarity during lysis.
Ultimately, whatever chemical you have in the lysis buffer either helps with breaking open the cells to extract the molecules you are aiming for, or aids in preserving your target molecules once your cells lyse.
References
Dean and Ward. 1992. The use of EDTA or polymyxin with lysozyme for the recovery of intracellular products from Escherichia coli. Biotechnology Techniques. Volume 6, pages 133-138.
Falgenhauer et al. 2021. Evaluation of an E. coli Cell Extract Prepared by Lysozyme‐Assisted Sonication via Gene Expression, Phage Assembly and Proteomics. Chembiochem. 22(18): 2805–2813
Rodríguez-Peña et al. 2013. Activation of the yeast cell wall integrity MAPK pathway by zymolyase depends on protease and glucanase activities and requires the mucin-like protein Hkr1 but not Msb2. FEBS Letters. Volume 587, Issue 22, 15 November 2013, Pages 3675-3680
Shehadul Islam et al. 2017. A Review on Macroscale and Microscale Cell Lysis Methods. Micromachines. 8(3):83
