| intracellular toxin | <protein> Heat stable polysaccharide like toxin bound to a bacterial cell. The term is used more specifically to refer to lipopolysaccharide (LPS) of the outer membrane of gram-negative bacteria. There are three parts to the molecule, the Lipid A (six fatty acid chains linked to two glucosamine residues), the core oligosaccharide (branched chain of ten sugars) and a variable length polysaccharide side chain (up to 40 sugar units in smooth forms) that can be removed without affecting the toxicity (rough LPS). Some endotoxin is probably released into the medium and endotoxin is responsible for many of the virulent effects of gram-negative bacteria. (18 Nov 1997) |
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| t-2 toxin | <chemical> (3 alpha,4 beta,8 alpha)-12,13-epoxytrichothec-9-ene-3,4,8,15-tetrol 4,15-diacetate 8-(3-methylbutanoate). A potent mycotoxin produced in feedstuffs by several species of the genus fusarium. It elicits a severe inflammatory reaction in animals and has teratogenic effects. Chemical name: Trichothec-9-ene-3,4,8,15-tetrol, 12,13-epoxy-, 4,15-diacetate 8-(3-methylbutanoate), (3alpha,4beta,8alpha)- (12 Dec 1998) |
| tetanus toxin | <protein> Neurotoxin released by Clostridium tetani, becomes active when peptide cleaved proteolytically to heavy (100 kD) and light (50 kD) chains held together by disulphide bond. Heavy chain binds to disialogangliosides (GD2 and GD1b) and part of the peptide (the amino terminal B fragment) forms a pore: light chain is a zinc endopeptidase that specifically attacks synaptobrevin, to block neurotransmitters. See: botulinum toxin (18 Nov 1997) |
| toxin | <pharmacology> A poison, frequently used to refer specifically to a protein produced by some higher plants, certain animals and pathogenic bacteria, which is highly toxic for other living organisms. Such substances are differentiated from the simple chemical poisons and the vegetable alkaloids by their high molecular weight and antigenicity. Origin: Gr toxikon = arrow poison, from Gr. Toxikos = of or for a bow (18 Nov 1997) |
| toxin spectrum | A figure in the form of a spectrum used by Ehrlich to represent the neutralizing power of antitoxin in the presence of toxin, toxone, etc. (05 Mar 2000) |
| erythrogenic toxin | <protein> Toxin produced by strains of Streptococcus pyogenes responsible for scarlet fever. Three antigenic variants of the toxin are known. It is a small protein that is complexed with hyaluronic acid and can intensify the effects of other toxins such as endotoxin and streptolysin O. (18 Nov 1997) |
| extracellular toxin | <protein> Toxin released from gram-positive and gram-negative bacteria as opposed to endotoxins that form part of the cell wall. Examples are cholera, pertussis and diphtheria toxins. Usually specific and highly toxic. (18 Nov 1997) |
| acetyl-CoA:alpha-glucosaminide acetyltransferase | <enzyme> An enzyme involved in the synthesis of certain carbohydrate moieties on proteins. A deficiency of this enzyme leads to mucopolysaccharidosis type III C. (05 Mar 2000) |
| adrenergic alpha-agonists | Drugs that selectively bind to and activate alpha adrenergic receptors. (12 Dec 1998) |
| adrenergic alpha-antagonists | Drugs that bind to but do not activate alpha-adrenergic receptors thereby blocking the actions of endogenous or exogenous adrenergic agonists. Adrenergic alpha-antagonists are used in the treatment of hypertension, vasospasm, peripheral vascular disease, shock, and pheochromocytoma. (12 Dec 1998) |
| alpha | First letter of the Greek alphabet, a. (05 Mar 2000) |
| alpha-1,3-mannosylglycoprotein beta-1,4-N-acetylglucosaminyltransferase | <enzyme> Incorporates n-acetyglucosamine as the third branch of complex n-glycosyl-oligosaccharide of hen oviduct Registry number: EC 2.4.1.145 Synonym: glcnac-transferase iv, n-acetylglucosaminyltransferase iv, udp-glcnac-gngn(glcnac to man alpha1-3)beta 4-n-acetylglucosaminyltransferase iv (26 Jun 1999) |
| alpha-1,4-glucan lyase | <enzyme> Degrades alpha-1,4-glucan to produce 1,5-anhydrofructose; from seaweeds gracilariopsis lemaneiformis and gracilaria verrucosa; mw 111 kD; amino acid sequence has been determined Registry number: EC 4.2.2.- Synonym: alpha-1,4-glucan 4-lyase (26 Jun 1999) |
| alpha 1-4-mannosyltransferase | <enzyme> From mycobacterium smegmatis; involved in methylmannose polysaccharide elongation; GDP-mannose is donor Registry number: EC 2.4.1.- (26 Jun 1999) |
| alpha(1-6)mannosidase | <enzyme> Human lysosomal enzyme highly specific for alpha 1-6 mannose residues; inhibited by swainsonine; not the same enzyme which is deficient in alpha-mannosidosis Registry number: EC 3.2.1.- (26 Jun 1999) |