6 replies to this topic

[dahui]

Do you add the sodium pyruvate into the DMEM or 1640 meduim which is bought from company? someone tell me the sodium pyruvate will be degrade 50% two weeks. So if my meduim stay more than two weeks, the 200mM sodium pyruvate should be added.

[leelee]

Are you sure you (or the person who you spoke to) aren't thinking of L-glutamine? L-glutamine is an unstable amino acid and so is often added to media just before use (media stored in fridge, L-glu stocks at -20C).

I'm pretty sure that sodium pyruvate is stable in the fridge for at least a year or so.

[madelingirly]

I buy medium from company Nacalai tesque with L-Glutamine and sodium pyruvate already added.
they said  if properly stored (2-8) it will be good till expiration date 1-2013   ????

[leelee]

The media will be fine for that long, madelingirly, but you will definitely have to supplement with extra L-glu after about a month in the fridge.

[madelingirly]

what does this mean
leelee

So I shall added l-glutamine to any fresh new bottle I have from the company, as these bottles already stored in the main company???
Or you mean after opening for example???

[leelee]

Good question, regarding adding it to new media that has L-glu already in it. I'm not really sure what to advise you on that, I hope someone else has the answer.

I buy my media without L-glutamine, then buy the L-glu separately and store it in smaller aliquots at -20C and add it to each bottle of media as I need it.

We used to make our own L-glu containing media from powder , and in that case I would usually top up with more L-glu after about 1-2 months of storage at 2-8C.

[bob1]

Leelee is correct, the L-glut does degrade to form ammonia (IIRC).  You can just add more l-glutamine, but this should not be repeated more than two times, to prevent build up of the ammonium in the solution.