Saporin

• UniProt: P20656

Saporin is a plant, toxic protein compound (protein toxin). It is produced by the ordinary soapwort, Saponaria officinalis and can be recovered from this plant.

Description

Saporin consists of a single polypeptide chain and is produced by the plant in at least ten isoforms which differ in amino acid sequence and glycosylation, with an absolute molecular weight of about 27,000 to 30,000 Da. Saporin belongs to the group of plant ribosome - inactivating proteins ( RIPs ) that inactivate the protein, especially of mammalian cells.

Effect

Saporin cleaves from adenine from the 28S ribosomal rRNA and is therefore referred to as N- glycosidase. Cleavage of the adenine of the 28S rRNA occurs at adenine 4324th a result, the protein of the cell is stopped, and the cell dies. However, the N- glycosidase not limited to the 28S rRNA, but also allows the Adeninfreisetzung from other RNA and also DNA.

Saporin consists of only one polypeptide chain and is therefore referred to as type 1 RIP. In contrast, in Type 2 RIPs such as ricin, the receptor -binding domain of a second polypeptide chain of the so-called B- chain, located. For saporin, however, no such receptor - binding domain is described. The uptake into cells is not clear saporin. Intracellular transport of saporin differs obviously from the way that was described for ricin, as it is to enter the cytosol not transported to the endoplasmic reticulum through endosomes.

Use

Due to its high cytotoxic effect saporin immunotoxins is tested as a component of the chimeric toxins, and to the possible treatment of tumors. The coding DNA sequence of saporin is known and therefore allows the recombinant expression of saporin and saporin fusion proteins.

Credentials

• Glycosidase
• Herbal Gift
• Clinical Research