DEFINITION
The C20 fatty-di-acid is a twenty-carbon dicarboxylic-acid moiety attached to Tirzepatide at the lysine-20 side chain through a γGlu-2xOEG spacer. It functions as the albumin-binding element, occupying serum-albumin fatty-acid binding sites reversibly.
The chemistry is a step longer than Semaglutide's C18 fatty-di-acid. The extended chain contributes to Tirzepatide's high plasma protein binding and its reported plasma half-life of approximately five days.
WHY IT MATTERS
The C20 di-acid side chain is the structural key to Tirzepatide's once-weekly kinetics.
RELATED
Compounds