Amino acid sequence and biological activities of proteins from Parkia speciosa

Abstract

Parkia speciosa Hassk (sato) that found in the northern part of Malaysia as well as in the southern part of Thailand. Sato is a famous vegetable and economic plant of Thailand, because it has high nutrient and has many medicinal properties. For example, it uses for reducing blood pressure and anti-diabetic. The beans have a laxative effect and ∝-glucosidase inhibitor. The present study aimed to characterize proteins and study the bioactivities of Parkia speciosa seeds. The lectin was purified from a crude extract by 60% of (NH₄)₂SO₄ fractionation followed by specific adsorption on Concanavalin A Sepharose and used by Methyl-∝-D-manopyranoside as eluent, gave total lectin 13.484 mg. The molecular weight of purified lectin determined by 1D-denaturetion gel electrophoresis were 45 kDa (C2a) and 23 kDa (C2b). Furthermore, the lectin were separated from a crude extract by 25% of (NH₄)₂SO₄ fractionation by affinity chromatography on Affi-gel blue gel and gel filtration chromatography on Superdex 200 are 21 kDa (Gj) and the 45 kDa (Al) showed inhibiting property of -∝-glucosidase were purified by HPLC. The 45 kDa and 21 kDa were found the molecular weight by 1D-SDS PAGE and MALDI-TOF MS, respectively. From peptides mass mapping by MALDI-TOF MS. and amino acid sequence database searching, the amino acid sequence of protein spot C2a, C2b are shown eight, six-peptides sequence similar to partial amino acid residue of Q69JW1_ORYSA from Oryza saliva and Q8VXY3_ARATH from Arabidopsis thaliana, respectively. The amino acid sequence from peptides mass mapping database searching from A1 and Gj are similar to partial amino acid sequence of Q9LDD9_ORYSA and Q8LN52_ORYSA from Oryza sativa.