Amyloid precursor protein is itself phosphorylated at T654, which is critical for subsequent cleavage into amyloid beta in a cellular neuronal AD model [110]; other PTMs occur on amyloid cleavage products, as well, including oxidation, phosphorylation, nitration, racemization, isomerization, pyroglutamylation, and glycosylation–involved in different physiological and pathological amyloid properties that may regulate disease progression [111]. Here, APP is linked to Alzheimer disease.