A comparative study of gelatin and dextran as sedimentation agents for neutrophil isolation during myeloperoxidase purification

Abstract

Myeloperoxidase (MPO), a haem-containing enzyme abundant in human neutrophils, significantly contributes to host defense and serves as a biomarker in cardiovascular and inflammatory diseases. Conventional purification methods employ dextran sedimentation for neutrophil isolation; however, dextran is costly and often unavailable. This study compared a gelatin-based sedimentation approach with the conventional dextran method to evaluate the suitability of gelatin as a cost-effective alternative for the purification of myeloperoxidase (MPO) from whole venous blood. Gelatin was used instead of dextran for neutrophil sedimentation before Ficoll centrifugation and hypotonic lysis of contaminating erythrocytes. A myeloperoxidase-rich fraction was prepared from whole neutrophil via selective salt precipitation, and the enzyme activity yield and specific activity were determined. The gelatin-based procedure produced MPO with a specific activity of 5.12 U/mg, 4.7-fold purification, and 42% yield, closely comparable to the 5.41 U/mg, 4.8-fold, and 43.2% values obtained using dextran. The Reinheit Zahl (RZ) value also showed parallel progression (0.39 vs. 0.43), confirming comparable purity. These findings demonstrate that gelatin is a viable, efficient, and economical substitute for dextran in neutrophil sedimentation during MPO purification. The method provides a reproducible, cost-effective approach for laboratories in developing economies to obtain high-quality MPO suitable for biochemical and diagnostic applications.