chymosin

from WordNet (r) 3.0 (2006)

chymosin
    n 1: an enzyme that occurs in gastric juice; causes milk to
         coagulate [syn: {rennin}, {chymosin}]

from The Collaborative International Dictionary of English v.0.48

Rennin \Ren"nin\ (r[e^]n"n[i^]n), n. (Biochem.)
   A milk-clotting enzyme obtained from the true stomach
   (abomasum) of a suckling calf. Mol. wt. about 31,000. Also
   called {chymosin}, {rennase}, and {abomasal enzyme}. --[Merck
   Man. 11]
   [1913 Webster]