(Science: chemical) N(2)-(1-(n(2)-l-threonyl)-l-lysyl)-l-prolyl)-l-arginine. A tetrapeptide produced in the spleen by enzymatic cleavage of a leukophilic gamma–globulin. It stimulates the phagocytic activity of blood polymorphonuclear leukocytes and neutrophils in particular. The peptide is located in the fd fragment of the gamma-globulin molecule.
Chemical name: L-Arginine, N2-(1-(N2-L-threonyl-L-lysyl)-L-prolyl)-