I'm new to enzymes and I would like to receive all possible help for this. I have a product that initially contains 57.9g of starch, which I would like to hydrolyze with alpha amylase, that has an activity of 1,11,793 U/G. How much grams of this enzyme should I add to the product so that all of the starch (57.9g) breaks down?
There are three problems with your question:
- You will never break down all substrate, eventually you'll reach equilibrium. In case of starch, however, that equilibrium is far on the right side.
- Even a tiny amount of enzyme will, eventually, break down (almost) all the starch. The more enzyme you use, the faster that will happen. The enzyme activity is the amount of product produced per unit time. In your case, 1 U = 1 µmol/min. However, this unit is outdated, you should work with katal (1 kat = 1 mol/s, 1 U = 16.7 nkat).
- The activity contains two commas, and thus is not a valid decimal figure
The molecular mass of glucose is 180.16, from that you need to subtract the water used in hydrolysis (18.02), thus from your 57.9 g of Starch you can produce 0.357 mol of glucose. From that amount and the time in which you wish the reaction to finish, you can calculate how many kat of enzyme you need, and using the specific activity you can convert that into g.
Hi there,
alpha amylase is actually unable to fully hydrolyse starch into glucose on its own. At best it will produce dextrins, maltose and maltotriose but no glucose as this enzyme is a strict endo(alpha1,4) glucohydrolase meaning it is not able to cleave the terminal bond of a starch linear oligosaccharide which would free glucose.
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