Brazzein and pentadin are a sweet-tasting protein produced in the fruit of the West African climbing plant Oubli (Pentadiplandra brazzeana Baillon) and found in the pulp tissue surrounding the seeds (Ming and Hellekant, FEBS Letters). Brazzein and pentadin are now thought to be the same protein.Similar to other sweet proteins discovered in plants, such as monellin (Morris et al. J. Bio. Chem) and thaumatin (Liu et al. Plant Cell Reports), it is extremely sweet compared to sucrose with sweetness 2000 to 4000 times that of sucrose (Faus and Sisniega).
The monomer protein, consisting of 53 or 54 amino acid residues, is the smallest of the sweet proteins with a molecular weigh of 6.5 kDa (Ming and Hellekant, FEBS Letters). The structure of brazzein was determined by proton nuclear magnetic resonance (NMR) and shown to have four evenly spaced disulfide bonds, an alpha-helix and three beta strands forming an anti-parallel beta sheet (Caldwell et al. Nature Struc. & Mol. Biol.). Brazzein is stable over a broad pH range from 2.5 to 8 and heat stable at 98°C for 2 hours.