IUBio

[Protein-analysis] Re: Help with calculations for specific activity

Dr Engelbert Buxbaum via proteins%40net.bio.net (by engelbert_buxbaum from hotmail.com)
Tue Oct 14 15:19:14 EST 2008


Am 30.09.2008, 16:55 Uhr, schrieb Fasulo, Lisa M  
<lisa.m.fasulo from pfizer.com>:

> I am trying to calculate the specific activity of my [3H]-ligand but
> don't know how to do it.  The package insert for my radioligand states
> that the Specific Activity is 200 mCi/g but I need to know what the
> Specific Activity is in Ci/mmol.  How do I calculate this?  The
> molecular weight of the radioligand is 463.6 g/mol.  Can anyone walk me
> through the calculations to give the specific activity in Ci/mmol?  The
> only other info I have is the concentration of the radioligand which is
> 1mCi/mL.

You use the rule of proportions (also known as rule of 3) for such  
calculations, i.e. if 463.6 g equals 1 mol (1000 mmol), how many mmol is 1  
g?

If 1 g has the activity of 200 mCi, and 1 ml contains 1 mCi, how many g  
are there in a ml (and by similar argument, how many mmol)?

Btw, the Curie (Ci) as unit of radioactivity is outdated by some 50 years,  
we use the Bequerel (Bq) now.


More information about the Proteins mailing list

Send comments to us at biosci-help [At] net.bio.net