Figure 1From: Evidence that an APOE ε4 'double whammy' increases risk for Alzheimer's disease Structure of apoE3 and apoE4. The polymorphism at residue 112 (which can be either arginine in apoE4 or cysteine in apoE3) is believed to underlie the differential antioxidant activities of apoE3 and apoE4 (adapted from [5], with permission).Back to article page