Substance P (1-4)

Substance P (1-4) is a fragment which is hydrolyzed from substance P by a prolyl endopeptidase. It seems to stabilize substance P against proteolytic degradation, to modulate the activity of substance P on various tissues, to exert a stimulatory effect on phagocytes and to release histamine from mast cells. Substance P 1-4 fragment is critical for mast cell activation. Replacement of the N terminal sequence of bradykinin with the aa 1-4 of Substance P (RPKP) enhanced the inhibitory activity of bradykinin on aminopeptidases