Preparation and application of Procion Yellow starch for amylase assay

A new starch derivative for the determination of amylase activity has been synthesized by coupling Procion Yellow dye with starch. The product of this reaction is intensely yellow and is easily suspended in water, in neutral buffer solution, and also in acidic solution. Amylase from pancreatin, saliva, urine and serum readily hydrolyzes this chromogenic substrate. A method for determining amylase activity based on the use of Procion Yellow Starch substrate is described. The procedure requires 0.1 ml of sample and an incubation time of 30 min. The soluble chromogen, which is liberated by enzymatic hydrolysis, is measured at 420 nm and the amylase activity-absorbance relationship at this wavelength is linear. The normal range for this method is 50--150 Somogyi units/dl.