Biochemical properties of beta-glucosidase in leukocytes from patients and obligated heterozygotes for Gaucher disease carriers.
BACKGROUND
Gaucher's disease (GD) is a disorder caused by the deficiency of lysosomal beta-glucosidase, an enzyme that participates in the degradation of glycosphingolipids. Deficiency of this enzyme results in the storage of glucocerebrosides in lysosomes of macrophage. No studies are available in the literature comparing biochemical and kinetic behavior of this enzyme in leukocytes and fibroblasts from normal individuals, obligate heterozygotes and patients with GD.


METHODS
The behavior of beta-glu in terms of optimum pH, heat stability, Km and Vmax in leukocytes from patients with GD and obligated heterozygotes with different genotypes and normal individuals were characterized.


RESULTS
Optimum pH was similar in all groups analyzed. In terms of Km and Vmax, several differences among heterozygotes and homozygotes groups and among these groups and normal enzyme were observed. Enzyme from all groups were inactivated when preincubated at 60 degrees C, but some enzymes were more stable than other. Results showed a different behavior of the enzyme in the 3 groups under analysis. Such behavior varied according to individual mutation.


CONCLUSIONS
The catalytic gradient presented by beta-glu allowed the correlation of N370S mutation-which presented more stable biochemical properties-with the non-neurological clinical condition of the disease and the catalytically less stable mutation (D409H), with the neurological clinical condition of GD. This study contributes to a better understanding of the repercussion of the different mutations on the protein function, thus allowing to predict the severity of such complex metabolic disorder and to anticipate the most appropriate intervention for each case specifically.
Michelin
Kristiane
K
Medical Genetics Service, Hospital de Clínicas de Porto Alegre, RS, Brazil.
Wajner
Alessandro
A
Bock
Hugo
H
Fachel
Angela
A
Rosenberg
Roberto
R
Pires
Ricardo Flores
RF
Pereira
Maria Luiza Saraiva
ML
Giugliani
Roberto
R
Coelho
Janice Carneiro
JC
D004795:Enzyme Stability; D005776:Gaucher Disease / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D006579:Heterozygote; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007962:Leukocytes / Q000201:enzymology* / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D011489:Protein Denaturation; D001617:beta-Glucosidase / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism*
D001617:beta-Glucosidase