Reference no: EM13211579
One of the key steps in brewing beer (or brewing root beer, if you prefer) is conversion of starch stored the barley into di- and trisaccharides through a process called "mashing" of the grain. Mashing involves the activation of two enzymes within the barley grains: alpha-amylase, which can hydrolyze starch at (alpha 1-->4) glycosidic linkages in non-reducing ends and beta-amylase, which recognizes the reducing end of starch molecules and hydrolyzes a glycosidic linkage to release a maltose unit.
a) Provide the full chemical name for the disaccharide maltose.
b) If you treated a 10 mM starch (a polysaccharide of ~ 30,000 D-glucopyranose monomers) solution with 10 umol of a -amylase alone, eventually the enzyme would break the entire polysaccharide into di/trisaccharides, but it would likely take 10-12 hours. Similarly, if you treated the same solution of starch with 10 umol of b-amylase alone, it too would eventually break the entire polysaccharide into smaller sugars, but it would take 16-18 hours. Assume the enzymes catalyze their reactions with similar rates. Why does it take more time for b -amylase to digest starch fully than a -amylase?
c) In contrast to part b, if you treat the starch solution with 5 umol of a -amylase and 5 umol of b -amylase, the polysaccharide can be fully digested in 2-3 hours. If both enzymes catalyze their reaction with similar rates, explain why the hydrolysis of the starch molecule is accelerated when both enzymes act together.