enkephalin vs endorphin

enkephalin and endorphin both are nouns.

Word	Noun	Adjective	Verb	Adverb
enkephalin	Yes	No	No	No
endorphin	Yes	No	No	No

As nouns, endorphin is a hypernym of enkephalin; that is, endorphin is a word with a broader meaning than enkephalin:

enkephalin: an endorphin having opiate qualities that occurs in the brain and spinal cord and elsewhere
endorphin: a neurochemical occurring naturally in the brain and having analgesic properties

enkephalin (noun)	endorphin (noun)
an endorphin having opiate qualities that occurs in the brain and spinal cord and elsewhere	a neurochemical occurring naturally in the brain and having analgesic properties