ABSTRACT
Peroxisomes were classically described as single membrane-bound organelles with a homogenous non-compartmentalized matrix that may contain a single electron-dense core (de Duve and Baudhuin, 1966). Urate oxidase is present in liver peroxisomes of most mammals and is localized exclusively in the crystalloid cores (Hruban and Swift, 1964; Leighton et al., 1969). This enzyme is lacking in hepatic peroxisomes of man, and these peroxisomes do not contain cores (Goldfischer and Reddy, 1984). However, it should not be taken for granted that peroxisomes lacking cores also lack uricase as this enzyme is present in soybean nodule peroxisomes which lack cores (Nguyen et al., 1985).
