human liquor human liquor human liquor means waste content from bowels isolated to investigate specific enzymes and peptidases involved in enteric contraction and digestion of compounds. p-endopeptidase isolated from human liquor inactivates tachykinins. hydrolysis of substance p by p-endopeptidase yields the active fragment of substance p. a neuroactive peptide, substance p is found throughout the central and peripheral nervous system. it has mostly been studied for its contractive effect on enteric musculature.