Defect in Amyloid protein folding occurs in:

PROTEIN MISFOLDING AND DISEASES- (1) Amyloidosis - Amyloids is used to refer to the altered proteins (with beta-sheets) that accumulate in the body, paicularly in the nervous system Alzheimer's disease is a neurodegenerative disorder Accumulation of beta amyloid. Other example of amyloidosis:- Type Protein Implicated Primary Principally light chains of immunoglobulins Secondary Serum amyloid (A (SAA) Familial Transthyretin; others:- apolipoprotein A-1, Cystain C, fibrinogen, gelsolin, Lysozyme Alzheimer's disease Amyloid b peptide (see Chapter 57, case no. 2) Dialysis - related b2 - microglobulin (2) Prion disease - Etiology:-Proteinaceous infectious agents No change in 1o structures and post translation modification Change in 3D structures (major change is replacement of alpha helix by beta sheets) Can act as template to conve non-infectious proteins (with cl-helices) to infectious forms Example - Transmissible spongiform encephalopathies (TSEs) and Creutzfeldt Jakob disease in humans. Scrapie disease - sheep Bovine spongiform encephalopathy (popularly known as mad cow disease) in cattle