Didemnin

Didemnins are a class of anti-tumor, anti - proliferative, anti - viral, and protein biosynthesis -inhibiting substances, the first from sea squirts ( Ascidiacea ) as Trididemnum solidum were extracted. However, their actual synthesis is most likely due to bacteria because the needed genes (so-called did- cluster) on plasmids as well as the Didemnin synthesis were detected in the α - Proteobacteria Tistrella mobilis and Tistrella bauzanensis.

Chemically include didemnins to the depsipeptides and consist of annular closed, partly modified amino acids, functional to the other groups or compounds of other classes are bound. These peptides are synthesized by ribosomes, but peptide synthases. Didemnin B will presumably arises from precursor molecules that are modified extracellularly.

In a study of the mechanism of action of didemnin B to the protein has been shown that didemnin B, along with other general anti- proliferative effects, effectively inhibits the translocation of eukaryotic ribosomes, by interacting with the elongation factor EF -1, and guanosine diphosphate (GDP ) a complex forms, which remains bound to the ribosome and thereby inhibits the translocation and successive protein extension. Due to its anti- proliferative properties were and some of the didemnins be explored as anticancer drugs. So, for example, is a closely related compound of Didemnin B, the dehydrodidemnin B ( Aplidin, Plitidepsid ), from the sea squirt Aplidium albicans from the Spanish pharmaceutical company PharmaMar SA tested. Studies with Didemnin B were reinstated due to the high cytotoxicity.