Proteomics of manila tamarind seeds Pithecellobium dulce

Pithecellobium dulce Benth. belongs to the Leguminosae family, which contains important components of human diets owing to their high protein content. The present study aimed to identify seed proteins from Pithecellobium dulce using a proteome approach by two-dimensional gel electrophoresis (2-DE) and tandem mass spectrometry. The 2-DE protein map revealed a total of 317 distinct protein spots, including a cluster proteins located in the acidic region with molecular masses of 55–97 kDa. Ninety-six of the most abundant protein spots were analysed using nano liquid chromatography/tandem mass spectrometry (nano-LC/MS/MS), from which 27 proteins and further four proteins from the highly abundant protein cluster were successfully identified through the query of acquired tandem mass spectral data used in Mascot and MS-driven BLAST homology searches, respectively. Moreover, the biological activity of Pithecellobium dulce seed proteins was identified in this research. An antifungal activity protein toward Macrophomina phaseolina with a molecular mass of 14.4 kDa was purified using a procedure that involved Tris buffer extraction, ammonium sulfate precipitation, anion exchange chromatography, and gel filtration chromatography. The result acquired from tandem mass spectrometry with Mascot database searching shows that this protein has partial amino acid sequences similar to chicken egg white lysozyme.