Biomaterial Database

Gliotoxin inactivates alcohol dehydrogenase by either covalent modification or free radical damage mediated by redox cycling. 1995

P Waring, and A Sjaarda, and Q H Lin

John Curtin School of Medical Research, Australian National University, Canberra City.

The fungal metabolite gliotoxin shows selective toxicity to cells of the immune system and has been implicated in the aetiology of invasive aspergillosis. The related toxin sporidesmin is the causative agent of facial eczema in sheep. The toxicity of these compounds has been related to their ability to redox cycle intracellularly and thus produce damaging free radicals. These toxins are also potentially capable of forming mixed disulphides with thiol groups on proteins by virtue of their bridged disulphide structure. We show here that gliotoxin can inactivate horse liver alcohol dehydrogenase by either oxidative damage or covalent modification of thiol groups on the enzyme. Either Cys-281 or Cys-282 is selectively modified. Neither of these residues are at the active site. Covalent modification occurs in the absence of reducing agents such as dithiothreitol. In the presence of dithiothreitol no protection is observed and the rate of inactivation is enhanced although as expected no covalent modification occurs. Gliotoxin can therefore inhibit alcohol dehydrogenase by either pathway and this will depend on the availability of reducing agents such as glutathione and/or how readily the reactive oxygen species generated are removed.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D002918	Chymotrypsin	A serine endopeptidase secreted by the pancreas as its zymogen, CHYMOTRYPSINOGEN and carried in the pancreatic juice to the duodenum where it is activated by TRYPSIN. It selectively cleaves aromatic amino acids on the carboxyl side.	Alpha-Chymotrypsin Choay,Alphacutanée,Avazyme
D004229	Dithiothreitol	A reagent commonly used in biochemical studies as a protective agent to prevent the oxidation of SH (thiol) groups and for reducing disulphides to dithiols.	Cleland Reagent,Cleland's Reagent,Sputolysin,Clelands Reagent,Reagent, Cleland,Reagent, Cleland's
D005609	Free Radicals	Highly reactive molecules with an unsatisfied electron valence pair. Free radicals are produced in both normal and pathological processes. Free radicals include reactive oxygen and nitrogen species (RONS). They are proven or suspected agents of tissue damage in a wide variety of circumstances including radiation, damage from environment chemicals, and aging. Natural and pharmacological prevention of free radical damage is being actively investigated.	Free Radical
D005912	Gliotoxin	A fungal toxin produced by various species of Trichoderma, Gladiocladium fimbriatum, Aspergillus fumigatus, and Penicillium. It is used as an immunosuppressive agent.	Aspergillin,Gliotoxins
D005978	Glutathione	A tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides.	Reduced Glutathione,gamma-L-Glu-L-Cys-Gly,gamma-L-Glutamyl-L-Cysteinylglycine,Glutathione, Reduced,gamma L Glu L Cys Gly,gamma L Glutamyl L Cysteinylglycine
D000426	Alcohol Dehydrogenase	A zinc-containing enzyme which oxidizes primary and secondary alcohols or hemiacetals in the presence of NAD. In alcoholic fermentation, it catalyzes the final step of reducing an aldehyde to an alcohol in the presence of NADH and hydrogen.	Alcohol Dehydrogenase (NAD+),Alcohol Dehydrogenase I,Alcohol Dehydrogenase II,Alcohol-NAD+ Oxidoreductase,Yeast Alcohol Dehydrogenase,Alcohol Dehydrogenase, Yeast,Alcohol NAD+ Oxidoreductase,Dehydrogenase, Alcohol,Dehydrogenase, Yeast Alcohol,Oxidoreductase, Alcohol-NAD+
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein