Hello! I am currently struggling with a specific issue and would appreciate some guidance.

The problem is that when using a buffer (I used a PBS buffer) for sonication to lyse cells, all the proteins seem to aggregate in the insoluble fraction.

One of my lab members tested this protein with various buffers and mentioned that soluble proteins were obtained when only using water for sonication.

So, when using water for sonication, even though there is still a large amount of insoluble material, we are able to obtain soluble proteins.

I suspect that aggregation might be happening due to the ionic strength during sonication.

What can I test to better understand the cause of this?

Has anyone had a similar experience or knows why this happens?

Any insights would be greatly appreciated!