chemist vs Melvin Calvin

chemist and Melvin Calvin both are nouns.

Word	Noun	Adjective	Verb	Adverb
chemist	Yes	No	No	No
Melvin Calvin	Yes	No	No	No

chemist (noun)	Melvin Calvin (noun)
a scientist who specializes in chemistry	United States chemist noted for discovering the series of chemical reactions in photosynthesis (1911-)
a health professional trained in the art of preparing and dispensing drugs