Comparative study of the efficacies of nine assay methods for the dextransucrase synthesis of dextran.

A comparative study of nine assay methods for dextransucrase and related enzymes has been made. A relatively widespread method for the reaction of dextransucrase with sucrose is the measurement of the reducing value of D-fructose by alkaline 3,5-dinitrosalicylate (DNS) and thereby the amount of D-glucose incorporated into dextran. Another method is the reaction with (14)C-sucrose with the addition of an aliquot to Whatman 3MM paper squares that are washed three times with methanol to remove (14)C-D-fructose and unreacted (14)C-sucrose, followed by counting of (14)C-dextran on the paper by liquid scintillation counting (LSC).