Echinocandin inhibition profiles for product-entrapped 1,3-β-d-glucan synthase enzyme complexes assessed by the incorporation of [3H]glucose into radiolabeled product. (A) CSF titration curves for enzymes isolated from strains ATCC 90030 (wild type), 5847 (Fks1p-S629P), and 3830 (Fks2p-S663P). (B) ANF inhibition curves for 1,3-β-d-glucan synthase enzyme complexes extracted from strains ATCC 90030 (wild type), 42997 (Fks1p-S625S), 234 (Fks2p-S659V), and 41026 (Fks2p-F659S).