hemin vs protohemin

hemin and protohemin both are nouns.

Word	Noun	Adjective	Verb	Adverb
hemin	Yes	No	No	No
protohemin	Yes	No	No	No

As nouns, hemin and protohemin are synonyms defined as:

hemin and protohemin: a reddish-brown chloride of heme; produced from hemoglobin in laboratory tests for the presence of blood

hemin (noun)	protohemin (noun)
a reddish-brown chloride of heme; produced from hemoglobin in laboratory tests for the presence of blood	a reddish-brown chloride of heme; produced from hemoglobin in laboratory tests for the presence of blood