Abstract: It is intended to provide a method by which a substance having a phosphate group can be easily detected from a biological sample or the like, a method by which a phosphorylated amino acid residue is easily identified and a compound which can be used in the methods because of having a high coordinate bond forming capacity with a substance having a phosphate group.

Abstract: Precipitation fractionation of an aqueous extract of soybeans by addition of an organic solvent such as ethanol or molecular weight fractionation of the extract by ultrafiltration or size exclusion chromatography is appropriately combined with activated carbon filtration, cation- or anion-exchange resin treatment or other adsorbent (e.g., polyamide or octadecylsilica) treatment to provide a nicotianamine product of desired purity. The product is added to food and drink to provide health foods.

Abstract: Precipitation fractionation of an aqueous extract of soybeans by addition of an organic solvent such as ethanol or molecular weight fractionation of the extract by ultrafiltration or size exclusion chromatography is appropriately combined with activated carbon filtration, cation- or anion-exchange resin treatment or other adsorbent (e.g., polyamide or octadecylsilica) treatment to provide a nicotianamine product of desired purity. The product is added to food and drink to provide health foods.

Abstract: Precipitation fractionation of an aqueous extract of soybeans by addition of an organic solvent such as ethanol or molecular weight fractionation of the extract by ultrafiltration or size exclusion chromatography is appropriately combined with activated carbon filtration, cation- or anion-exchange resin treatment or other adsorbent (e.g., polyamide or octadecylsilica) treatment to provide a nicotianamine product of desired purity. The product is added to food and drink to provide health foods.

Abstract: Disclosed in this invention are a novel enzyme producing tartaric acid ether compound which catalyzes a reaction of producing a tartaric acid ether compound in which the phenolic hydroxyl group(s) of a flavonoid or its analogous compound having at least one phenolic hydroxyl group is (are) acted to the epoxy ring of an epoxysuccinic acid to form ether linkage of one or more tartaric acid residues, a process for producing a tartaric acid ether compound by acting the enzyme in the presence of an epoxy-succinic acid and a flavonoid or its analogous compound having at least one phenolic hydroxyl group, and novel tartaric acid ether compounds in which the epoxy ring of an epoxysuccinic acid is bound to the phenolic hydroxyl group(s) of a flavonoid or its analogous compound to form ether linkage of one or more tartaric acid residues. These compounds are useful as a component material of pharmaceuticals and functional foods.