Approximatly 38,000 people in Ireland are affectedby Alzheimer’s, a figure which is growing every day. Because this disease is soprominent in our society it is important for us, as chemists, to not only beaware of the facts and statistics, but also what chemical reaction andimbalances make this disease as devastating and fast acting as it is. In peoplediagnosed with dementia and Alzheimer’s, there is shrinking of the CerebralCortex which is the part of the brain that deals with remembering and planning,But what causes this to happen? Prezi.com Beta Amyloid, which denote peptides of amino acids,are crucially involved in Alzheimer’s disease. This protein clumps and tanglestogether to form plaques in the fatty membrane that surrounds the nerves of thebrain. These clumps then block signals and communication to and from the brain.Once these cell membranes are damaged the cells themselves can die whichcontributes to the massive loss of brain mass that ultimately brings ondementia and Alzheimer’s.
This Beta Amyloid has no use in the body and is onlya byproduct of a metabolic process.PlaquesThese plaques form when specific proteins in theneurons cell membrane are processed differently. Normally, an enzyme calledalpha-secretase snips APP, an amoloid precursor protein, which releases afragment while a second enzyme, Gamma secretase, also snips the protein inanother place. These released fragments are thought to benefit neurons.
However, in Alzheimer’s patients, the first snip of the protein is made usuallyby another enzyme Beta secretase. This cut combined with the cut made by gammasecretase results in the release of short fragments called beta amoloid. Whenthese beta amoloid fragments come together and become insoluble eventuallyforming clumps and plaques.Neurofibrillary tanglesThese are created when a protein called Tau ismodified.
In normal brain cells, these proteins stabilise structures criticalto cells internal transport system. Nutrients and other cellular cargo arecarried up and down structures called microtubules to all parts of the neuron.In Alzheimer’s patients , abnormal Tau separates from the microtubules causingthem to fall apart. Strands of this then dislodged Tau clump together to formtangles inside the neuron which disables the transport system and ultimatelydestroys the cell. Pbsnewshour