Leukocyte beta-glucosidase in homozygotes and heterozygotes for Gaucher disease.

摘要: Human leukocytes contain at least two isozymes of 4-methylumbelliferyl-beta-glucosidase acting optimally pH 4.0 and 4.8; in Gaucher disease, only the former is deficient. Brief exposure leukocyte homogenate to room temperature results irreversible inactivation 4.8 activity, while activity remains unaffected. The more acidic isozyme stimulated four- fivefold by 0.2% sodium taurodeoxycholate (TDC) with a shift optimum 5.0. less completely suppressed presence this detergent. Both appear be membrane-bound since gel filtration Sephadex G-200 produces one peak located void volume, unlike liver kidney where second also can demonstrated. Heat analysis indicated that controls, assayed absence detergent, thermostable than activity. However, residual beta-glucosidase just as thermolabile unaffected enzyme TDC resulted rapid loss suggesting direct effect bile salt on configuration decreasing its thermal stability. In acid shows K(m)'s, 3.2 mM another 0.9 mM. higher K(m) 3.3 obtained. patients disease obligate carriers, essentially V(max) expected deficiency.A reliable reproducible selective assay technique has been developed for diagnosis homozygotes heterozygotes carrier screening individuals risk inherited disorder. efficacy demonstrated studying 42 26 patients, 32 heterozygotes, 23 healthy relatives disease.