ATTENTION ALL REPORTERS: The research findings cited in this release were not presented at the American Chemical Society national meeting because the researcher was not available to make the presentation.

Washington D.C., August 23 -- A "striking similarity" between proteins involved in the early stages of Alzheimer's disease and mad cow disease was described here today at the 220th national meeting of the American Chemical Society, the world's largest scientific society. The theory, if verified by other researchers, could help focus efforts to develop preventive drugs, according to the study's lead researcher, Chi Ming Yang, Ph.D., a professor of chemistry at Nankai University in Tianjin, China.

Prion diseases which include, among others, neurodegenerative diseases such as mad cow disease and its human counterpart, Creutzfeldt-Jakob disease are caused by a malfunctioning prion protein. In Alzheimer's disease, another neurodegenerative disease, the amyloid precursor protein has been implicated.

Using computer modeling, Yang discovered a similar pattern of amino acids in the prion protein and the amyloid precursor protein: 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," says Yang.

Reductive amino acids are more prone to damage by oxygen-containing free radicals (molecules with a highly reactive unpaired electron) than other amino acids, explained Yang. Normally, the body can clear itself of free radicals. But with age, this system may fail. When enough free radicals accumulate to damage a protein molecule, it can malfunction, he says.

Proteins typically fold into specific three-dimensional structures that determine their functions. A malfunctioning protein may remain partially unfolded,
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Contact: Charmayne Marsh
c_marsh@acs.org
202-872-4445
American Chemical Society
23-Aug-2000