Isolation and characterisation of a novel cysteine-rich peptide from momordica charantia seeds

• Main Author: Low, Ee Lynn
• Other Authors: Liu Chuan Fa
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Science::Biological sciences
• Online Access: https://hdl.handle.net/10356/171858
• Institution: Nanyang Technological University

Momordica charantia, a fruit commonly known as bitter gourd or bitter melon, belongs to the Cucurbitaceae family, which is well known to contain plant species abundant in cysteine-rich peptides. A lot of attention has been directed to members of this family for the antimicrobial properties of cysteine-rich peptides. In this study, we identified and isolated a novel cysteine-rich peptide from the seeds of Momordica charantia using reverse-phase high-performance liquid chromatography, chemical modification of cysteine residues, and matrix-assisted laser desorption ionization time-of-flight mass spectrometry to identify a molecular weight of 3139 Da corresponding to the novel peptide. Trypsin and chymotrypsin digestion was done for manual de novo sequencing of the peptide via b-ions and y-ions assignment. De novo sequencing resulted in proposed sequences for two fragments of the peptide. A minimum inhibitory concentration assay was also conducted to explore the potential antimicrobial activity of this novel peptide. The peptide did not display significant antibacterial activity against Escherichia coli, Staphylococcus aureus, and Methicillin-resistant Staphylococcus aureus at a peptide concentration of 100 µg/mL. The classification and innate function of this peptide have yet to be uncovered.