GLUL and Alzheimer disease: Some specifically oxidized proteins have been identified in neurodegenerative brains: (i) creatine kinase (CK), which decreases the ATP supply in synaptic terminals (necessary to drive ion-motive pumps or to synthesize antioxidant proteins); and (ii) glutamine synthetase (GS) and the glutamate transporter Glt-1, which can induce injury in the AD brain via glutamate excitotoxicity, for example.