Accumulation of intracellular autofluorescent material or aging pigment has been characterized as a normal aging event. Lipofuscin (from the Greek word for fat and the Latin word for dark), refers to intracellular autofluorescent material that accumulates in aging cells with a excitation wavelength between 320 and 480 nm and an emission wavelength between 460 and 630 nm. Lpofuscin consists of a mixture of oxidized proteins and lipids, carbohydrates and trace amount of metals. Ceroid iss a lipofuscin-like lipopigment that arises from pathological conditions such as disease, malnutrition, and cell stress. Subunit c of mitochondrial ATP synthase makes up approximately 40% of this lipopigment/ceroid accumulation.