Introduction

Another globular protein, amyloid β protein (Aβ), plays an important role in Alzheimer's disease (AD). This is a devastating disease that, if left unchecked and untreated, threatens to affect over 13 million Americans by the year 2050 [520]. About one in ten people over the age of 65 and as many as five out of ten people over the age of 85 are affected by AD. In the twentieth century, it was found by looking at deceased patients suffering from Alzheimer's that the brains of such individuals contained plaques and neurofibrillary tangles [521–523]. Over the past 20 years, we have gained a more molecular understanding of the causes of AD. Indeed, the primary protein component of these plaques was sequenced [524, 525]; in addition, the protein that is the building block of the neurofibrillary tangles has now been sequenced. Such knowledge has obviously led to a focused concentration on these phenomena. Indeed, at first it was believed that these plaques and tangles were the prime causes of the disease. Recent studies, however, point to another possible cause. In this chapter we summarize our progress in understanding AD. Although our understanding of the disease is still developing, the mechanisms causing AD are better understood.