NCATS-SM1441 (compound 52) is a lactate dehydrogenase ( LDH ) inhibitor ( IC 50 =40 nM). By inhibiting the activity of LDH , NCATS-SM1441 is able to reduce the production of lactic acid in cancer cells, helping to slow or stop the proliferation of cancer cells. NCATS-SM1441 can be used to study cancer metabolism.