Currency metabolites vs. current metabolites: What's the right term?
Currency refers to anything that is used in any circumstances, as a medium of exchange [1]. That's why ATP and NAD are considered as currency metabolites [2]. So currency metabolite can be used for any metabolite that has multiple uses in different reactions/pathways.

Current refers to something that is prevalent at the present time [3]. So current metabolite is used to refer a metabolite that is already available for a specific reaction/pathway and doesn't need to undergo supplementary transformations to fit for that specific reaction. 

The same metabolite can be simultaneously a currency metabolite and a current metabolite for a specific situation.



References:


Wikipedia contributors, "Currency," Wikipedia, The Free Encyclopedia, http://en.wikipedia.org/w/index.php?title=Currency&amp;oldid=611672968 (accessed July 12, 2014).
Gerlee P, Lizana L, Sneppen K. Pathway identification by network pruning in the metabolic network of Escherichia coli. Bioinformatics. 2009 Dec 15;25(24):3282-8. doi: 10.1093/bioinformatics/btp575. PubMed PMID: 19808881. 
The Free Dictionary by Farlex. http://www.thefreedictionary.com/current