Converting pmol/L to pg/mL?

Ian Davis Ian.Davis at
Mon Jul 31 16:19:52 EST 2000

At 07:56 31/07/00 -0700, you wrote:
>"Ian Davis" <Ian.Davis at> wrote ...
>> MW is about 21,000 daltons (unglycosylated), so 1 pmol/L = 21,000 pg/L =
>> 21 pg/mL.
>        Thanks, Ian. I'm assuming "MW" here means "IL-6 MW." How much would
>the MW change if the IL-6 were glycosylated? The paper I'm trying to
>decypher does not mention glycosylation.

Up to about 28 kDa.  Check the context: if it's natural IL-6 eg in serum
or cell supernatant, it's probably glycosylated.  If it's exogenous lab
IL-6 it's probably E coli derived and so unglycosylated.

>> IL-1 MW = 17kDa.  TNF MW = 17kDa (secreted form, not membrane bound).
>        How much difference would it make if it were membrane bound? For my
>immediate purposes, a few percent won't matter.

26 kDa transmembrane form.  This won't be available in supernatants.

>Dear Dr. Davis,
>        Thank you for helping Little Russell make up his homework. I don't
>know what I'm going to do with that boy! He spends years chasing submarines
>and designing command and control systems, but do you think he will take
>five minutes and clean up his room? He was probably down in Brazil again
>tracking those darn astronauts when he missed his chemistry classes.
>                                                Russ' Mom

Thanks Mrs Farris.  It's good to hear from you again after all those
years, especially since...The Incident....  I'll never forget that
night...but I digress.

>        Seriously, I would like to find a table with some of these MW
>values. Can you recommend a good reference book? I know that CRC published a
>lot of great reference books for engineers, but biochemistry is a new field
>for me.

On my lap helping me appear wise is The Cytokine Handbook, Thomson A
(ed), 3rd edition, San Diego: Academic Press, 1998.

Hope this helps, I know how annoying this can be.


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