3-Mercaptopropionic acid (3-Sulfanylpropanoic acid) is an intermediate in the metabolism of organosulfur in the natural environment and is commonly used in nanoparticles.

5-羟色胺是来自动物的天然产物。

This is amino acids 86 to 100 fragment of class II-associated invariant chain peptide called CLIP. The major histocompatibility complex class II molecule displays peptide fragments of foreign proteins to trigger a defensive reaction from the immune system. Before insertion of the foreign peptides into the binding groove, a place-holding peptide CLIP is removed. This is accomplished by the molecule DM, which is shown to increase the dissociation rate of a CLIP peptide from class II.