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# Problem with calculations for enzyme activity

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### #1 maja_l

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Posted 08 May 2014 - 03:17 PM

I know it sounds trivial but i have some problems with calculations for the experiment that I've performed today in the lab. I was supposed to do the bioassay for the lysozyme, using 3 samples: crude, precipitation, dialysis and of course standards.

Preparation of satndards: 1mg lysozyme/ml of stock with/ spec activity of 47080 U/mg that needed to be diluted 20 times (I've used a total volume of 500ul, so 25ul in 475 ul of potassiumphosphate buffer)

Stand 1:

150 ul of potassiumphosphate buffer

150ul of diluted lysozyme stock

then what is enzyme activity in the standard solution (U/ml)?

I keep making some mistakes and i'm pretty sure of it

### #2 bob1

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Posted 08 May 2014 - 03:43 PM

So your stock solution is at 1 mg/ml and therefore has 47080 U/ml and you want to know the concentration after dilution

C1V1=C2V2

47080 (U/ml) * 25 (ul) = 500 (ul) x C2

C2=??? U/ml

You can use the same equation to work out your stand 1.

### #3 maja_l

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Posted 08 May 2014 - 11:01 PM

thanks

i was using the concentration for it as 1mg/ml.. and then calculating it further to U/ml

I guess some calculations are usually way easier than I'm thinking