Biomedicine

Abstract

Caesalpinia mimosoides, a medicinally significant plant, harbors bioactive compounds, including hydrolytic enzymes such as esterases. Carboxyl esterases (CEs) play crucial roles in metabolic processes and have wide-ranging industrial relevance. However, limited information is available on the biochemical characterization of esterases from C. mimosoides seeds. This study aimed to isolate, purify, and characterize carboxyl esterases from the seeds of C. mimosoides, with an emphasis on understanding their properties for potential application in biotechnology and allied fields. Protein extracts were obtained from seed acetone powder, followed by enzyme purification through ammonium sulfate precipitation (0–60%), ion-exchange chromatography using DEAE-cellulose, Sephadex G-100 gel filtration, and preparative polyacrylamide gel electrophoresis (PAGE). The enzyme was characterized using SDS-PAGE, native PAGE, and isoelectric focusing. Enzyme kinetics, substrate specificity, thermal and pH optima, stability, and inhibitor sensitivity were assessed using standard spectrophotometric assays with 1-naphthyl esters. The purified CE showed a molecular mass was approximately 30.2–31.1 kDa, and the isoelectric point was 7.4. The enzyme demonstrated optimal activity at pH 7.5 and 45°C and retained activity between pH 4.0–9.0 and temperatures up to 60°C. Substrate specificity analysis revealed a preference for α-naphthyl butyrate. Kinetic parameters indicated a higher affinity for 1-naphthyl propionate compared to α-naphthol acetate. Inhibitory studies showed significant sensitivity to organophosphates (phosphomidon, dichlorvos), while resistance was observed to eserine sulfate and PCMB. The carboxyl esterase from C. mimosoides seeds is a stable monomeric enzyme with distinct biochemical features, making it a promising candidate for applications in industrial catalysis and environmental bioremediation.