Selank is a synthetic heptapeptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) derived from the immunomodulatory tetrapeptide Tuftsin (Thr-Lys-Pro-Arg) with a C-terminal Pro-Gly-Pro extension that enhances metabolic stability and CNS activity. This modification provides anxiolytic effects absent in parent Tuftsin.
Medicinal chemistry research demonstrates how the Pro-Gly-Pro addition transforms Tuftsin's immune function into Selank's neuropsychiatric activity.