Martin E. Mulligan mulligan at kean.ucs.mun.ca
Tue Aug 11 18:49:55 EST 1992

In article <1992Aug11.083145.1474 at gnv.ifas.ufl.edu>, afc at gnv.ifas.ufl.edu (Andrew F. Cockburn) writes:
> In article <n62m_xn at lynx.unm.edu>, bhjelle at carina.unm.edu writes:
>> In article <1992Aug10.184231.25639 at gserv1.dl.ac.uk> skspoidn at uk.ac.rdg.susssys1 ("Mike Poidinger") writes:
>>>1) I don't think they did mean 32-P. They meant 33-P. 
>>>It's new on the market, supposed to have 5 times the 
>>>strength of 35-S, which is a lot less than 32-P
>> Also costs a lot more. I nixed that one right away when
>> NEN quoted a price.
> I looked in my 92/93 NEN catalog and saw that 33-P gamma ATP
> is actually cheaper than 32-P.  Of course that is list price,
> and I have never in my life paid list price for radioactivity.
> Was your quote for dNTPs instead?
> In any case, I would expect price to drop rapidly if demand 
> picks up.

Since we have used 33-P, I can make some comments about it.  Basically
we have been very happy with using it.  Our gels have been intense and
very readable after an overnight exposure.  My student claims that
he can decipher doublets and triplets much better with 33-P than
with 35-S.  We are still on our first (and probably only) batch, so
I can't comment on how long its usable life actually is.  I believe
that we have always removed the plastic-wrap after drying though -
force of habit from 35-S.

We tend to do sequencing in spurts of activity so I'm not sure
how useful the 33-P would be all the time.  I suspect that I would
always want to have 35-S around if we just needed to sequence once
in a while and did not want to invest in 33-P every couple of months
only to use very little of it.  Then, is we foresaw a lot os sequencing
gels ahead, we could (price willing) get the 33-P for that.

I did not think to try and get the g-labelled ATP for end-labelling
but the longer half-life of teh 33-P might be an advantage there.  
Sometimes, its difficult to judge when you will be ready to do
a primer extension reaction and we end up ordering the 32-P only
to watch it decay in the freezer before we are ready to use it.

As for the cost of 33-P, I certainly cannot afford to use it at the
current catalog price ($438 canadian).  I was able to get some
because last Fall had asked the NEN rep about teh possibility
of getting trial samples.  Nobody responded at that time, but
when I contacted the rep, he offerred to let me try some at the
same price as the 35-S dATP, which costs us CDN$70.  So, I would
suggest trying your local rep to see if he/she will let you
have some to try.  If enough people find that they like it,
and would use it, if only the price were the same, then NEN
might drop their prices.  Its a thought.

Martin E. Mulligan
Dept. of Biochemistry
Memorial University of Newfoundland    mulligan at kean.ucs.mun.ca

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