Many antibiotics and antiparasitic are based on an inhibition of the fotates biosynthesis pathway (vitamin B9). The regular appearance of resistance to these molecules leads to search for new molecules. In search of such inhibitors, researchers at our laboratory have developed a method for assaying the activity of enzymes involved in the biosynthetic pathway of folate. This assay method, compatible with a high throughput screening robotic platform, allowing them to identify such a molecule.