D-retro-inverso peptide design

A mirror-image peptide that proteases cannot chew

Ordinary peptides make poor drugs: the body's proteases shred them within minutes. FOXO4-DRI dodges this with a clever trick borrowed from chemistry, the D-retro-inverso design, which builds the molecule from mirror-image amino acids in reverse order so that its shape is preserved but its bonds are unrecognizable to those enzymes.

This unit explains what DRI actually means, why a cell-penetrating tag was bolted on, and the honest trade-offs the design carries.