Membrane‐bound sorbitol dehydrogenase in human red blood cells. Studies in normal subjects and in enzyme‐deficient subjects with congenital cataracts

Abstract

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.

Carbohydrate metabolism in erythrocytes of copper deficient rats11Publication # 538 of the Bureau of Nutritional Sciences.

“…Thus, fructose utilization is inhibited by the presence of glucose, and erythrocytes, unlike other tissues, do not phosphorylate fructose to any significant extent under normal conditions. These observations agree with data from human erythrocytes that showed sorbitol accumulation in response to external glucose, but not fructose [34,35] and show that an accumulation of sorbitol and sorbitol-phosphate could not account for the impairment of hematological parameters observed during copper deficiency.…”

Sorbitol dehydrogenase: a novel target for adjunctive protection of ischemic myocardium

“…forms of SDH have also been reported (14)(15)(16). The presence and function of SDH in heart remains to be understood.…”