Mercaptopropionaldehyde from homocysteine: implications for Alzheimer's disease.
There has been evidence for a causal relationship between homocysteine and Alzheimer's disease for several years but the mechanism is unclear. In vivo, some homocysteine is converted to the thiolactone. This report describes a novel reaction between homocysteine thiolactone and dehydroascorbic acid in which the homocysteine thiolactone is converted to 3-mercaptopropionaldehyde. This product is shown to react with proteins causing their precipitation (probably by cross-linking). The two reactions are extremely facile and appear to be physiologically compatible suggesting a mechanism by which homocysteine may promote the deposition of proteins in nerve cells as amyloid plaques and fibrillary tangles.
Toohey
John I
JI
Cytoregulation Research, Elgin, Ontario, Canada. cytoreg@xplornet.com
D015097:3-Mercaptopropionic Acid / Q000737:chemistry / Q000378:metabolism*; D000447:Aldehydes / Q000737:chemistry / Q000378:metabolism*; D000544:Alzheimer Disease / Q000378:metabolism* / Q000473:pathology; D016564:Amyloid beta-Protein Precursor / Q000378:metabolism; D011232:Chemical Precipitation; D006710:Homocysteine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D016874:Neurofibrillary Tangles / Q000378:metabolism / Q000473:pathology; D058225:Plaque, Amyloid / Q000378:metabolism / Q000473:pathology
D000447:Aldehydes; D016564:Amyloid beta-Protein Precursor; D006710:Homocysteine; D015097:3-Mercaptopropionic Acid; C007957:homocysteine thiolactone