# Bradford Assay - How do you calculate ug concentration??? (May/07/2009 )

I am new to lab and am unsure about bradford assays. How do you calculate ug concentration for a sample. If the assay tell me my protein is 5mg/ml, is that 5ug/ul? Do I need to multiple by the total volume? Also, if I did a 1:10 dilution of the lysate I multiply by mg conc. by 10?

I'm lost. Any help would be greatly appreciated. If someone would be so kind to explain or walk me thru this it would be so helpful!

-Scilyn

5 mg/ml = 5ug/ul. to work out how many ug you have c=n/v rearranged to get n=c*v will give you the answer. If you diluted, then you have to multiply by the dilution factor. These are basic chemistry questions, something you should have learned in science at 13-14. Sorry; not being mad at you, just at the school system that lets this sort of thing get passed by.

Thank you for the help. My confusion is when I have to figure out how much (in ul) to load of my lysate onto a gel. So, if I am using 100ul of lysis buffer, and I am using 5ul of a 1:10 dilution of the lysate, and my bradford says I have 2000 ug/ml, do I have to take into account that I have 100ul of total lysate? How does this math work out?

I know that if it is a dilution I have to multiple by 10, so that means 2000 ug/ml x 10? 20,000ug/ml? Which is 20mg/ml.

If I need to load 40ug onto my gel, how to I figure this out?

I appreciate the help, thanks again!

Use the same equation working out for v

v=n (40 ug)/ c (20, 000 ug/ml)

v= 40/20,000

v=0.002 ml

v=2 ul

Make sure you keep your units consistent (i.e. if working in ml, use ml not a combination of ml and litres or microlitres, same goes for mass, distance etc.)