Abstract
Using 4-meth-ylumbelliferyl-α-L-iduronide as a substrate, α-L-iduronidase activity was meas-ured in leukocytes and in lymphoblastoid cells obtained from patients with α-L-iduronidase deficiency and from obligate heterozygotes for this disease. There was complete discrimination between α-L-iduronidase activities measured using 4-methylumbelliferyl-α-L-iduronide in leukocytes and in lymphoblastoid cells from the patients and controls. However, overlap was observed between values of the activity in the obligate heterozygotes and those in the controls. 4-Methylumbelliferyl-α-L-iduronide is superior to phenyl-α-L-iduronide for the determination of α-L-iduronidase activity because of greater sensitivity, easier assay procedure and shorter incubation period.
