biochemical calculations

[ming_li]

could sumbody pleaze give me some direction with this questn?

I have 20mL of solution of 20mM [14C] pyruvate (50 dpm nmol-1). What would be the specific activity of the pyruvate if you add

(a) 30ml of water

(b)add 11mg of pyruvate (Mr pyruvate is 110)

[RobJim]

Does the [14C] refer to temperature or what? Also, what does dpm mean?

[sdekivit]

Originally Posted by RobJim

Does the [14C] refer to temperature or what? Also, what does dpm mean?

it's radioactively labelled pyruvate (pyruvate containing the C-14 isotope). Dpm stands for desintegrations per minute.

the specific activity means the activity per amount of pyruvate. It can be calculated by dividing the total activity by the amount of pyruvate in mg.

So when adding water, there's no change in the specific activity, since the amount of pyruvate doesn't change. Adding unlabelled pyruvate will lower the specifi activity of the pyruvate, since the amount of pyruvate in the solution rises.