Source : Webster's Revised Unabridged Dictionary (1913)

Ptyalin \Pty"a*lin\, n. [Gr. ? spittle. See {Ptyalism}.]
   (Physiol. Chem.)
   An unorganized amylolytic ferment, on enzyme, present in
   human mixed saliva and in the saliva of some animals.

Source : WordNet®

ptyalin
     n : an amylase secreted in saliva