The Km for ATP of PI4KA is 209 μM (53), and while inhibition of mitochondrial metabolism by NO, or other mitochondrial inhibitors, decreases β-cell ATP levels by ∼8- to 10-fold in INS832/13 cells (rat insulinoma cell line) and rat islets, mitochondrial inhibition depletes ATP levels by ∼50% in MIN6 cells (29, 54, 55). This evidence concerns the gene PI4KA and pancreatic insulinoma.