Abstract: A sweet protein, brazzein, has been discovered from the fruits of Pentadiplandra brazzeana B., a tropical wild plant in west Africa. Brazzein has 54 amino acid residues; it is 2000 times sweeter than sucrose (Ming and Hellekant, 1994 ). In this article, further characterization shows that its molecular weight is 6.5 kD and isoelectric point is 5. It has 8 cysteines and they form four disulfide bonds. After treating its aqueous solution at 80 ℃ for 4 hrs, no changes in sweetness and behavior of electrophoresis are found. Secondary structures predictions suggests that beta turns and beta sheets are the dominant structures in the protein.

Key words: Pentadiplandra brazzeana, Sweet protein brazzein, Chemicl modification