Cysteine in Alzheimer's Disease

Abstract

Alzheimer's disease (AD) is characterized by selective loss of neurons in the hippocampus and neocortex due to abnormalities in proteins, mainly Aβ peptide and tau protein, in the form of abnormal protein aggregations or depositions in neurons. Recently oxidative/nitrosative stress has been identified as an important facilitator of neurodegeneration in AD. Cysteine-dependent proteins are known to be associated with the neurodegenerative process. Such cysteine-dependent enzyme proteins are proteases, antioxidant enzymes, kinases, phosphatases, and also non-enzymatic proteins such that utilize cysteine as a structural part of the catalytic site. This chapter deals with the role of cysteine in handling reactive oxygen/nitrogen species during oxidative/nitrosative stress and posttranslational modification of proteins causing protein misfolding or protein aggregation during neurodegeneration associated with AD.