Pathways to selected lysergic acid-derived ergot alkaloids and DHLA-derived ergot alkaloids. Enzymes responsible for catalysis are listed at appropriate points. Double arrows indicate omission of one or more intermediates. Relevant ring and carbon labeling (referred to in text) is indicated on the lysergic acid, 9, structure. Ergovaline, 10, is shown as a representative of several possible 9-derived ergopeptines; dihydroergosine, 6, is the only known dihydroergopeptine. Abbreviations: DMAPP, dimethylallylpyrophosphate; dma, dimethylallyl; eas, ergot alkaloid synthesis; clo, clavine oxidase; lps, lysergyl peptide synthetase.