The tetronic acid, chlorothricin, is an unusual macrocyclic antibiotic from a Streptomyces sp., related to kijanimicin, saccharocarcins, tetrocarcins and versipelostatin. Chlorothricin inhibits cholesterol biosynthesis from mevalonate and inhibits pyruvate carboxylases purified from rat liver, chicken liver and Azotobacter vinelandii.