Description_x000D_ General description_x000D_ Chemical structure: macrolide_x000D_ Application_x000D_ The antibiotic virginiamycin is produced by Streptomyces virginiae and is a member of the virginiamycin family. Each member is produced as a mixture of two structurally different compounds that exhibit synergistic antibacterial activity. There are two groups: virginiamycin M1 (VM1) and virginiamycin S (VS). VM1 is a polyunsaturated macrocyclic petolide. VM1 and VS are both used to inhibit protein synthesis since they are bacteriostatic. When used in combination they are more effective. Virginiamycin is used as a performance promoter in animal husbandry. They are chemically modified to make therapeutic drugs such as quinupristin and dalfopristin._x000D_ Packaging_x000D_ 5, 10 mg in serum bottle_x000D_ Biochem/physiol Actions_x000D_ Virginiamycin M1 inhibits bacterial protein synthesis at the level of aminoacyl-tRNA binding and peptide bond formation. It inactivates the 50S ribosome. S. virginiae inactivates VM1 by reducing its 16-carbonyl group, forming 16R-dihydroVM1. VM1 reductase participates solely in VM1 inactivation in vivo._x000D_ Other Notes_x000D_ Keep container tightly closed in a dry and well-ventilated place.