Thiols in formaldehyde dissimilation and detoxification.
Glutathione is not a universal coenzyme for formaldehyde oxidation. MySH (mycothiol, 1-O-(2'-[N-acetyl-L-cysteinyl]amido-2'-deoxy-alpha-D-glucopyranosyl)-D-m yo-inositol) is GSH's counterpart as coenzyme in formaldehyde dehydrogenase from certain gram-positive bacteria. However, formaldehyde dissimilation and detoxification not only proceed via thiol-dependent but also via thiol-independent dehydrogenases. The distinct structures and enzymatic properties of MySH-dependent and GSH-dependent formaldehyde dehydrogenases could provide clues for development of selective drugs against pathogenic Mycobacteria. It is to be expected that other new types of thiol-dependent formaldehyde dehydrogenases will be discovered in the future. Indications exist that the product of thiol-dependent formaldehyde oxidation, the thiol formate ester, is not only hydrolytically converted into thiol and formate but can also be oxidatively converted in some cases by a molybdoprotein aldehyde dehydrogenase into the corresponding carbonate ester, decomposing spontaneously into CO2 and the thiol.
Duine
J A
JA
Department of Microbiology and Enzymology, Delft University of Technology, The Netherlands.
D000445:Aldehyde Oxidoreductases / Q000378:metabolism; D003545:Cysteine; D004187:Disaccharides / Q000378:metabolism*; D005557:Formaldehyde / Q000378:metabolism* / Q000493:pharmacokinetics; D005978:Glutathione / Q000378:metabolism; D006020:Glycopeptides; D006094:Gram-Positive Bacteria / Q000378:metabolism*; D008658:Inactivation, Metabolic; D007294:Inositol; D009161:Mycobacterium / Q000378:metabolism; D011720:Pyrazoles; D013438:Sulfhydryl Compounds / Q000378:metabolism*
D004187:Disaccharides; D006020:Glycopeptides; D011720:Pyrazoles; D013438:Sulfhydryl Compounds; C089265:mycothiol; D005557:Formaldehyde; D007294:Inositol; D000445:Aldehyde Oxidoreductases; C087006:formaldehyde dehydrogenase, glutathione-independent; D005978:Glutathione; D003545:Cysteine