Precipitation by organic acids: e.g. Picric acid
Organic acids carry a large negative charges which neutralize positively charged protein to form an insoluble salt. The acidic reagents are most effective at acid pH value where proteins are positively charged. The precipitation of proteins (e.g. Albumin or Gelatin) by this method is irreversible.
In this experiment, we can differentiate between Albumin & Peptone.
![](https://s2.save4k.ru/pic/g8tvl7LrEFI/maxresdefault.jpg)