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Title: Lens aldehyde reductase and cataract
Author: Halder, Anjana B.
ISNI:       0000 0001 3524 3318
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 1982
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Polyol dehydrogenase and aldehyde reductase B have been assayed in normal clear lenses of rat, rabbit, bovine, mouse and human. With DL-glyceraldehyde as substrate the percentage specific activitiesof aldehyde reductase are 60%, 16%, 6% and 1.6% in rabbit, human, bovine and mouse lenses respectively, taking the activity in rat lens as 100%. With D-glucose as substrate the specific activities followed a similar pattern. The specific activities of polyol dehydrogenase were 100%, 2.8% and 0, 0, 0 in human, bovine and rat, rabbit and mouse lens respectively. The properties of crude and of pure bovine lens aldehyde reductase B have been studied. Some properties of bovine polyol dehydrogenase have also been studied and compared to those of aldehyde reductase B. Aldehyde reductase B activity was located in the β-crystalline fraction of bovine lens. The enzyme was purified to apparent homogeneity (on SDS gel) by use of a combination of gelfiltration and ion-exchange chromatography . The purification showed that glyceraldehyde and glucose reducing activities purified to different extent. Chemical modification of bovine lens aldehyde reductase B showed that arginine and histidine are involved in catalytic function of the enzyme and are present at or near the NADPH binding site. A thiol group on the enzyme is necessary for acting with glucose. Studies with sulindac and FPL 58665, the inhibitors of aldehyde reductase B, showed that the enzyme has a different site for its inhibitors. Steady-state kinetic analysis showed that this enzyme obeys an ordered-Bi-Bi mechanism and NADPH is the first substrate to bind to the enzyme. Kinetic analysis showed that the binding of NADPH and glucose to the enzyme is 1:1 whereas with DL-glyceraldehyde the minimum degree of rate equation is 2:2. NADPH-oxidizing activity was measured with DL-glyceraldehyde in human blood and this activity was found to be elevated in diabetic patients suffering from retinopathy with or without cataract. This activity was also found elevated in patients with senile cataract. A scheme has been proposed relating aldehyde reductase B to cataract and diabetic retinopathy.
Supervisor: Grabbe, James Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Cataract ; Treatment ; Alcohol dehydrogenase