Miraculin

Miraculin is a natural sugar substitute, a glycoprotein extracted from the fruit of Synsepalum dulcificum. The berry, also known as the miracle fruit, was first documented by explorer Chevalier des Marchais, who searched for many different fruits during a 1725 excursion to its native West Africa.

Miraculin itself is not sweet. However, after the taste buds are exposed to miraculin (which binds to sweet receptors on the tongue), acidic foods which are ordinarily sour (such as citrus) are perceived as sweet. This effect lasts up to an hour.

The active substance, isolated by Prof. Kenzo Kurihara (栗原 堅三　Kurihara Kenzō), a Japanese scientist, was named miraculin after the miracle fruit when Kurihara published his work in Science in 1968.

Glycoprotein structure

Miraculin was first sequenced in 1989 and was found to be a glycoprotein consisting of 191 amino acids and some carbohydrate chains.

Miraculin occurs as a tetramer (98.4 kDa), a combination of 4 monomers group by dimer. Within each dimer 2 miraculin glycoproteins are linked by a disulfide bridge.