Four arginine/glutamate rich polypeptides referred to as 5k-, 6.5k-, 12.5k-, and 14k-AGRPs were purified to homogeneity by gel filtration on Sephadex G-75 followed by CM-cellulose, butyl-Toyopearl 650M, and reverse-phase HPLC from the seed of sponge gourd (Luffa cylindrica). Tricine SDS-PAGE indicated that 5k- and 6.5k-AGRPs are single polypeptides, but 12.5k- and 14k-AGRPs consist of two polypeptide chains, which are linked by disulfide bond(s). The N-terminal amino acid sequences of four AGRPs were analyzed by a gas-phase sequencer, and the result indicated that they are distinct molecules. Comparison of the sequences with those of proteins in the protein data base demonstrates that 5k- and 6.5k-AGRPs have a significant homology with a basic peptide from pumpkin seeds and with cocoa seed vicilin, respectively, and that 12.5k- and 14k-AGRPs are related to 2S seed storage proteins. Furthermore, it was assumed that the four AGRPs might occur in the protein bodies within cells of the seed.
All Science Journal Classification (ASJC) codes
- Analytical Chemistry
- Applied Microbiology and Biotechnology
- Molecular Biology
- Organic Chemistry