Membrane-bound sorbitol dehydrogenase in human red blood cells. Studies in normal subjects and in enzyme-deficient subjects with congenital cataracts.
Membrane-bound and soluble forms of erythrocyte sorbitol dehydrogenase (SORD) activity are compared in normal individuals. Both isoenzymes showed similar properties. In a family with red cell SORD deficiency and congenital cataracts, Km values for sorbitol and NAD+ as well as the effect of the enzymatic deficiency on sorbitol accumulation in red cells incubated in high-glucose or high-fructose media were determined. In SORD-deficient patients, the enzymatic deficiency was observed in both crude haemolysate and SORD-M preparations with sorbitol, galactitol, xylitol or ribitol as substrates. The mutation responsible for SORD deficiency did not modify the Km for sorbitol and NAD+. Finally, SORD deficiency produced a significant increase of sorbitol accumulation in red cells incubated in high-concentration glucose media and a significant decrease when the cells were incubated in high-concentration fructose media.
Alvarez
A
A
División de Genética, Instituto Mexicano del Seguro Social, Guadalajara, Jalisco.
Martínez
A
A
Ibarra
B
B
Medina
C
C
Bracamontes
M
M
Perea
J
J
Vaca
G
G
D002386:Cataract / Q000151:congenital* / Q000201:enzymology / Q000235:genetics; D004910:Erythrocyte Membrane / Q000201:enzymology*; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000097:blood; D007700:Kinetics; D007064:L-Iditol 2-Dehydrogenase / Q000097:blood* / Q000172:deficiency; D008297:Male; D010375:Pedigree; D010641:Phenotype; D013012:Sorbitol / Q000097:blood; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013379:Substrate Specificity
D007527:Isoenzymes; D013012:Sorbitol; D007064:L-Iditol 2-Dehydrogenase