Wiktionary
a. Preventing or counteracting pain; analgesic. n. (context biochemistry English) An oligopeptide, produced by ''Actinomycetes'' and other bacteria, that acts as a protease inhibitor
Wikipedia
Antipain is an oligopeptide isolated from actinomycetes and used in biochemical research as a protease inhibitor, reported in 1972 as the first natural peptide containing a ureylene group. Specifically, it is an inhibitor of trypsin and papain.
It has been crystallised in complex with carboxypeptidase from wheat and Leishmania major oligopeptidase B. In both cases the backbone carbonyl of the terminal arginine of antipain forms a covalent bond to the active site serine in the protease.
Usage examples of "antipain".
It hurts, so they invoke a local antipain spell and give me a spinal shot, but then my legs get numb and I can't walk.
Iris left arm was now in a sling, and he wore a packing of antipain potions.
Between the antipain drugs we'd been given and the glorious high of knowing that we had won a rough fight over impossible odds, I suppose I was getting insufferably pompous.