Source : Webster's Revised Unabridged Dictionary (1913)

Xanthoprotein \Xan`tho*pro"te*in\, n. [Xantho- + protein.]
   (Physiol. Chem.)
   A yellow acid substance formed by the action of hot nitric
   acid on albuminous or proteid matter. It is changed to a deep
   orange-yellow color by the addition of ammonia.