A fatty acid bundle is a packed multi-arm linker carrying 2 or 3 fatty acid molecules.

The fatty acids are mostly long-chain fatty acids. A fatty acid bundle is considered a targeting moiety for use in modifying an effector, such as a peptide hormone.

The modification of a peptide with a fatty acid is an established concept. However, the invention of fatty acid bundles allows the conjugation of two or more fatty acids onto a specific amino acid residue, such as a lysine residue, on the peptide or to the N or C terminal of the peptide.

The modification of a peptide drug with a fatty acid bundle enhances the association of the peptide with serum albumin and hence lengthen its circulation half-life better than a single fatty acid.

Typically, an azide or alkene group for click reaction or an SH-reactive group is installed at the end of coupling arm.

Here is an example of a fatty acid bundle.