A compound is provided which comprises at least a portion of an amino acid linker-domain from squalene synthase. In alternative forms, the compound can include the amino-acid linker-domain from various fungus, including S. cerevisiae or the compound can be the functional equivalent and/or mimics an amino acid linker-domain from squalene synthase. A pharmaceutical composition includes the compound and may further include a pharmaceutical carrier. A method is provided for treating or controlling cholesterol metabolism and ergosterol metabolism in non-fungal organisms. One method includes a therapeutic treatment in humans by administering a therapeutically effective amount of the compound or pharmaceutical composition, to a patient in need of treatment, therefrom.
