Enzyme Units

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Rufus's picture
Enzyme Units

Hello! Sorry if this sounds like a stupid question, but im not sure how to find out exactly what quantity of enzyme i need, if its described that I need 2U each, of beta-galactosidase, alpha-mannosidase and sialidase to react with Gc globulin.
 Thankyou for your help!

frangky's picture

You should measure you enzyme source with Gc globulin respectively, then calculate the unit, and you can quantity 2U which you need.

protoldo's picture
Hola, I don´t know if yuo

Hola, I don´t know if yuo have commercial or house made enzymes, but all the commercial enzymes have in the specifications weigh, units , and reconstitution volume if they are lyofilized, so you can know units/vol. If you have made in house ones attending their purity and volume, you put assay them to check the activity. In the sigma catalogue, you can compare activities with weights and find the method to assay them in order to know the activity. Good luck

proteaPam's picture
Hey Rufus,

Hey Rufus,

There is no such thing as a stupid question. The only stupid question is one not asked. It all depends on your source of your enzyme and how it is packaged. If you have a lyophilized enzyme in say 100U all you need to do is reconstitute in whatever volume you want. Now if you have a reconstituted enzyme it gets a little bit more tricky. It all depends on the vendor, but all the information you need is typically on the Certificate of Analysis (CQA) that came with your enzyme. The following information will help you calculate out the units: Activity (U/mL), specific activity (U/mg Protein), and unit definition (i.e. 1 Unit of enzyme will hydrolyze x amount of substrate per time at these parameters). I typically dilute to a concentration that is easy to work with (i.e. 1U/uL) and aliquot it out for later use (minimizes freeze/thaw cycles).

For example say I have an enzyme from a vendor and the activity is 500,000 U/mL (or 500,000U/1000uL) and I want 500uL 1U/uL enzyme to aliquot out. (You want to use the activity determined from the CQA because it is lot dependent)

use C1V1 = C2V2
500uL (1U/uL) = V2 (500,000U / 1000uL)
V2 = 1uL 500,000U/mL + 499uL ddH2O

I hope this helps! Good Luck!

With regards,

Pamela Williams
Laboratory Technician at Protea Biosciences, Inc.