A fluorimetric method for red blood cell sorbitol dehydrogenase activity

Area of Science:

• Biochemistry
• Clinical Chemistry
• Enzymology

Background:

• Sorbitol dehydrogenase (SDH) is an enzyme crucial in cellular metabolism.
• Quantifying SDH activity in red blood cells (RBCs) is important for diagnosing certain metabolic disorders.
• Existing methods for SDH quantification can be time-consuming or complex.

Purpose of the Study:

• To develop and validate a novel fluorimetric assay for quantifying RBC sorbitol dehydrogenase.
• To compare the new method with existing spectrophotometric assays.
• To assess the utility of the new method for large-scale screening.

Main Methods:

• The method relies on the enzymatic oxidation of sorbitol to fructose, using NAD+ as a cofactor.
• Red blood cell sorbitol dehydrogenase catalyzes this reaction, producing NADH.
• NADH is quantified using a filter fluorimeter.

Main Results:

• The fluorimetric method demonstrated good correlation with an indirect spectrophotometric assay.
• The new assay is significantly faster, simpler, and more cost-effective than the spectrophotometric method.
• The method is suitable for high-throughput screening of SDH activity.

Conclusions:

• A novel, efficient fluorimetric assay for RBC sorbitol dehydrogenase has been established.
• This method offers practical advantages in terms of speed, simplicity, and cost.
• The assay is well-suited for screening populations for sorbitol dehydrogenase deficiency, particularly in clinical settings involving diabetes and cataracts.