Search results
Results from the WOW.Com Content Network
Diphtheria toxin is a single polypeptide chain of 535 amino acids consisting of two subunits linked by disulfide bridges, known as an A-B toxin.Binding to the cell surface of the B subunit (the less stable of the two subunits) allows the A subunit (the more stable part of the protein) to penetrate the host cell.
The diphtheria toxin precursor is a protein of molecular weight 60 kDa. Certain proteases, such as trypsin, selectively cleave DT to generate two peptide chains, amino-terminal fragment A (DT-A) and carboxyl-terminal fragment B (DT-B), which are held together by a disulfide bond . [ 23 ]
A small amount (0.1 ml) of diluted (1/50 MLD) diphtheria toxin is injected intradermally into one arm of the person and a heat inactivated toxin on the other as a control. If a person does not have enough antibodies to fight it off, the skin around the injection will become red and swollen, indicating a positive result.
An example SDS, including guidance for handling a hazardous substance and information on its composition and properties. A safety data sheet (SDS), [1] material safety data sheet (MSDS), or product safety data sheet (PSDS) is a document that lists information relating to occupational safety and health for the use of various substances and products.
The diphtheria toxin gene is encoded by the bacteriophage found in toxigenic strains, integrated into the bacterial chromosome. [13] The diphtheria toxin repressor is mainly controlled by iron. It serves as the essential cofactor for the activation of target DNA binding. A low concentration of iron is required in the medium for toxin production.
CRM197 is a genetically detoxified form of diphtheria toxin. A single mutation at position 52, substituting glutamic acid for glycine, causes the ADP-ribosyltransferase activity of the native toxin to be lost. The structural basis for the lack of CRM197 toxicity has recently been elucidated. [4]
It is an IL2-receptor-directed cytotoxin. It is an engineered protein combining interleukin-2 and diphtheria toxin. [3] Medical uses
A toxoid is an inactivated toxin (usually an exotoxin) whose toxicity has been suppressed either by chemical or heat treatment, while other properties, typically immunogenicity, are maintained. [1] Toxins are secreted by bacteria, whereas toxoids are altered form of toxins; toxoids are not secreted by bacteria.