Ipomoea batatas (SWEET POTATO) PEEL PEROXIDASE AS AN ALTERNATIVE GLUCOSE OXIDASE- PEROXIDASE FOR SERUM GLUCOSE TEST

Abstract.  Diabetes mellitus is a chronic metabolic disorder characterized by elevated blood glucose levels and often requires regular monitoring to manage the condition and prevent complications. Accurate and accessible glucose testing is therefore essential, particularly in low-resource settings where the cost of commercial diagnostic reagents may be prohibitive. This study explores the potential of sweet potato peel (SPP) as a low-cost, plant-based source of peroxidase for use in glucose diagnostic testing, addressing the demand for accessible reagents in low-resource settings. The main objective was to develop and evaluate a modified glucose oxidase–peroxidase reagent by substituting commercial peroxidase with an enzyme extracted from 300 g of SPP. The peroxidase was partially purified through ammonium sulfate precipitation and dialysis, with protein content and enzymatic activity assessed via the Biuret test and guaiacol oxidation assay, respectively. The percent yield, specific activity (118 U/mg), and volume required (13.52 mL) to match 4800 units of commercial enzyme were determined. The modified reagent was tested on serum samples from 10 individuals and compared to a standard GOD-POD reagent in terms of accuracy, thermal and pH stability, and turnaround time. Results showed that the SPP-derived reagent performed comparably to the commercial counterpart under optimized conditions (pH 6.0, 2°C), indicating its viability as a substitute. This study demonstrates the potential of SPP peroxidase as a sustainable, cost-effective alternative for glucose testing, with practical implications for improving diagnostic accessibility in underserved communities  Keywords: accuracy, glucose testing, peroxidase, sweet potato peel, sustainability