Source : Webster's Revised Unabridged Dictionary (1913)

Elastin \E*las"tin\, n. [Elastic + -in.] (Physiol. Chem.)
   A nitrogenous substance, somewhat resembling albumin, which
   forms the chemical basis of elastic tissue. It is very
   insoluble in most fluids, but is gradually dissolved when
   digested with either pepsin or trypsin.

Source : WordNet®

elastin
     n : a fibrous scleroprotein found in elastic tissues such as the
         walls of arteries