# What exactly is peptone (tryptone?) and why does it not get precipitated?

According to Wikipedia Peptone (also called Tryptone) is a form of amino acid that has been treated by stomach acids. According to Google it also stays in solution when treated with acids or heat. Why is that so?

Some protones are animal-based and some are plant-based. For instance, peptone water is a microbial growth medium composed of peptic digest of animal tissue and sodium chloride. The $$\mathrm{pH}$$ of the medium is $$7.2\pm 0.2$$ at $$\pu{25 ^\circ C}$$ and is rich in tryptophan. Peptone water is also a non-selective broth medium which can be used as a primary enrichment medium for the growth of bacteria (Ref.1).