. . . "As these de novo???formed peroxisomes are found in only about half of the cells, we conclude that de novo formation is a slow process (taking more than one cell generation time) and results in cells that are temporarily devoid of peroxisomes.The ER to peroxisome pathwayDeletion of PEX3 or PEX19 results in a complete absence of peroxisomal structures (Hettema et al., 2000)." .