White Blood Cell Acid Hydrolases in Leukaemias, Mucopolysaccharidoses and Mannosidosis

Simple, synthetic substrates, commercially available, were used for assay of five acid hydrolases (β‐galactosidase, β‐glucosidase, α‐mannosidase, N‐acetyl‐β‐glucosaminidase, and β‐glucuronidase) in human white blood cells from 23 controls and 25 patients with inborn storage disorders or leukaemia. Conditions for release of the enzyme activities, pH‐dependency, and properties on gel filtration and isoelectric focusing are described. In chronic myelocytic leukaemia high activities of α‐mannosidase were found, whereas the activities of all enzymes were low in chronic lymphocytic leukaemia. In acute myeloblast leukaemia enzyme activities varied. In two cases of mannosidosis very low values of α‐mannosidase were found.