act upon vs influence

act upon is not a noun while influence is a noun.

Word	Noun	Adjective	Verb	Adverb
act upon	No	No	Yes	No
influence	Yes	No	Yes	No

As verbs, act upon and influence are synonyms defined as:

Other synonyms of act upon include work.

act upon (noun)	influence (noun)
	causing something without any direct or apparent effort
	a power to affect persons or events especially power based on prestige etc
	a cognitive factor that tends to have an effect on what you do
	one having power to influence another
	the effect of one thing (or person) on another

act upon (verb)	influence (verb)
have and exert influence or effect	shape or influence; give direction to
	induce into action by using one's charm
	have and exert influence or effect