Diphtheria toxin is an exotoxin secreted by Corynebacterium diphtheriae, the pathogen bacterium that causes diphtheria. An exotoxin is a soluble chemical excreted by a microorganism, including bacteria, fungi, algae, and protozoa. ... Binomial name Corynebacterium diphtheriae Kruse, 1886 Corynebacterium diphtheriae is a pathogenic bacterium that causes diphtheria. ... A pathogen or infectious agent is a biological agent that causes disease or illness to its host. ... Subgroups Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular: bacterium) are microscopic, unicellular organisms. ...

Diphtheria toxin is a single polypeptide chain of 535 amino acids consisting of two subunits linked by disulfide bridges. Binding to the cell surface of the less stable of these two subunits allows the more stable part of the protein to penetrate the host cell.^[1] Peptides are the family of molecules formed from the linking, in a defined order, of various amino acids. ... In structural biology, a protein subunit or subunit protein is a single protein molecule that assembles (or coassembles) with other protein molecules to form a multimeric or oligomeric protein. ... A disulfide bond (SS-bond), also called a disulfide bridge, is a strong covalent bond between two sulfhydryl groups. ... In biology, a host is an organism that harbors a parasite, mutual partner, or commensal partner, typically providing nourishment and shelter. ...

It catalyzes the ADP-ribosylation and inactivates the eucaryotic elongation factor-2 (eEF2). It does so by ADP-ribosylating the unusual aminoacid diphtamide. In this way, it acts as a DNA translational inhibitor. ADP Ribosylation Factors (ARFs) are members of the ARF family of GTP-binding proteins of the RAS superfamily. ... In chemistry, an amino acid is any molecule that contains both amino and carboxylic acid functional groups. ... Translation is the second process of protein biosynthesis (part of the overall process of gene expression). ...

Diphtheria toxin is extraordinarily potent.^[1] The lethal dose for humans is about 0.1 μg/kg of pure protein. A massive realease of toxin into the body will likely cause lethal necrosis of the heart and liver.^[2] A lethal dose (LD) is an indication of the lethality of a given substance or type of radiation. ... Necrosis (in Greek Νεκρός = Dead) is the name given to unprogrammed death of cells and living tissue. ... The heart and lungs, from an older edition of Grays Anatomy. ... The liver is the largest internal organ of the human body. ...

Diphteria toxin was discovered in 1890 by Emil Adolf von Bering.

References

1. ^ ^a b Murphy JR (1996). ''Corynebacterium Diphtheriae: Diphtheria Toxin Production In: Baron's Medical Microbiology (Baron S et al, eds.), 4th ed., Univ of Texas Medical Branch. (via NCBI Bookshelf) ISBN 0-9631172-1-1.
2. ^ Pappenheimer A (1977). "Diphtheria toxin.". Annu Rev Biochem 46: 69-94. PMID 20040.