What does it mean if I am given 40U of enzyme?

Question

raspberryjam · Answer

U as in mu the greek letter? Does it look like this? μ?

anonymous · Answer

U as in units of enzyme activity

raspberryjam · Answer

Ohhh gotcha. It's the amt of enzymes that will convert 1 micromol of substance per min.

raspberryjam · Answer

Er I meant substrate not substance

anonymous · Answer

yeah. got that part. i'm trying to find the final enzyme concentration. the problem just said 40 units of Hae enzyme.

raspberryjam · Answer

It didn't tell you the amount of substrate that got converted?

raspberryjam · Answer

Or give you a time lol?

anonymous · Answer

Maybe i'm interpreting the question incorrectly but this is what i have: Set up a dna digest of the sample that contains 10 ug of dna sample & 40 units of Hae III enzyme. the ff is given: stock dna = 3.5ug/ul ; enzyme stock is 12units/ul.

raspberryjam · Answer

So wouldn't that just be $$\frac{40u}{12u}=3.33\mu L $$ of the enzyme? Then $$\frac{10\mu g}{3.5\mu g}=2.86\mu L $$

raspberryjam · Answer

is it asking you to make a specific volume of it?

anonymous · Answer

thanks! i actually figured it out last night while we were talking about it! it was a duh! moment for me. yes, i would need 3.33uL of the enzyme. wish me luck on my midterm!

raspberryjam · Answer

Haha you won't need it :)

anonymous · Answer

so how do you calculate your final volume when you have 3.33ul of enzyme, 3.5ug/ul of stock and 3.33 uls of 10X buffer?

anonymous · Answer

I forgot to say I have 2.85uls of DNA.