Fig. 1.

Using targeted and untargeted metabolomics to decipher enzyme and pathway functions. A and B: functional targeted and untargeted metabolomic platforms (A) have arisen to assist in characterizing the functions of metabolic enzymes in complex biological systems (B). In a typical functional metabolomic experiment, one can comparatively profile alterations in the metabolome, comparing a control group to impairment or overexpression of a given metabolic enzyme in a complex biological or disease sample. This experiment can be comparing groups such as wild-type (+/+) vs. knockout (−/−) samples, vehicle- vs. enzyme inhibitor-treated samples, shControl vs. shEnzyme, or control vs. enzyme overexpression. Elevated or reduced metabolites from blocking an enzyme will assist in assigning substrate/product relationships but also metabolic pathway connectivities.