Mad Cow And Alzheimer's
Proteins Are Similar
WASHINGTON (Reuters) - Proteins linked with Alzheimer's and the human version of mad cow disease have some striking similarities -- and thus might be susceptible to similar treatments, a researcher said on Wednesday.
Both diseases are marked by a gradual deterioration of the brain and both are associated with rogue proteins. Both are always fatal.
Chi Ming Yang, a professor of chemistry at Nankai University in Tianjin, China, said he used a computer model to map the prion protein associated with Creutzfeldt-Jakob disease (CJD), the human equivalent of mad cow disease, and the amyloid precursor protein associated with Alzheimer's.
Proteins are made up of amino acids, and Yang told a meeting of the American Chemical Society in Washington that he found a similar pattern of amino acids in the two proteins -- a reductive amino acid followed by three non-reductive amino acids.
``This suggests a common molecular mechanism underlying the initiation stages of sporadic Alzheimer's disease and both sporadic and genetic prion diseases,'' he said in a statement.
Reductive amino acids are more prone to damage by free radicals -- the molecules than can damage cell DNA in the same chemical process that underlies rusting.
Alzheimer's is the most common cause of dementia, affecting an estimated 12 million people worldwide. The cause is not known but hallmarks of the disease include messy ``tangles'' of nerve fibers and ``plaques'' rich in the amyloid proteins.
CJD is the human version of bovine spongifirm encephalitis (BSE or mad cow disease). It occurs naturally in about one in a million people but a new version linked with eating BSE-infected meat has turned up in Britain.
Prion proteins that do not fold normally are believed to cause BSE and CJD.

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