Glutamine: fructose-6-phosphate amidotransferase, its production and use

A method for screening for a compound which promotes or inhibits the enzyme activity of glutamine:fructose-6-phosphate amidotransferase, the method comprising

• a) contacting a substrate with a protein having an amino acid sequence represented by SEQ ID NO:1, a partial peptide or a salt thereof, wherein said partial peptide, or salt thereof, has the activity of glutamine:fructose-6-phosphate amidotransferase;
• b) measuring the enzyme activity of the protein, the partial peptide, or a salt thereof;
• c) contacting the substrate and a test compound with the protein, the partial peptide or a salt thereof;
• d) measuring the enzyme activity of the protein, a partial peptide of the protein, or a salt thereof;
• e) comparing the activity in b) with the activity in d), wherein a difference in activity indicates that the test compound is a compound which promotes or inhibits the enzyme activity of the protein.