Effect of albumin on amylase assay using blue starch polymer

The nature of the stimulation by albumin of amylase activity determined by use of blue starch polymer was studied. The binding of albumin to the starch polymer was responsible for the stimulation of amylase activity, since the stimulation was observed with the albumin-bound blue starch polymer as substrate irrespective of the presence or absence of free albumin in the reaction mixture. When the albumin-bound blue starch polymer was hydrolysed by amylase, the blue oligosaccharide fragments were released with the albumin attached. These oligosaccharide fragments were about 1.3 times larger in average molecular size than the fragments released in the absence of albumin, suggesting that the apparent stimulation of amylase by albumin, (about 1.3 times) is due to the liberation of the larger oligosaccharide fragments.