Mary-ann,
The Jasco J-810 is quite a new model so you'll probably not find much of an
experience base with that particular one. It appears that model is very
similar to the J-715 that we bought a year ago.
Most of the data we take for clients are purposes similar to your
applications, such as showing comparability after process changes or
examining thermal stability, and we are very pleased with of J-715 for these
purposes. (Some example applications are shown on our web site,
http://www.ap-lab.com/circular_dichroism.htm)
One nice feature of the Jasco 715 and 810 is that the lamp is air cooled
rather than water cooled (especially important for us here in California
where dumping cooling water down the drain is a no-no, but also a plus for
reliability and portability). By using more efficient optics Jasco gets
signal/noise performance equivalent to a much higher wattage, water-cooled
lamp.
I certainly recommend a Peltier temperature controller on any machine you
buy for ease in doing thermal unfolding studies. Both Jasco and Aviv now
offer options for doing automatic titrations (pH or denaturants) and
simultaneous fluorescence measurements as well. Those things are probably
nice if you do an awful lot of detailed folding studies, but I'm not sure
they are really needed for pharmaceutical applications.
The Aviv instruments work quite well also. There are those users that swear
by Aviv, and those who swear by Jasco, and each camp tends to denigrate the
other instrument (but with few hard facts to back that up). I think the
actual optical performance of both is pretty similar, but nonetheless these
preferences can engender strong loyalties and biases similar to those about
PCs versus Macintosh.
I think CD buyers sometimes get too hung up on arguments over performance at
190 nm and below. While clearly these low wavelength data help in getting a
more accurate analysis of secondary structure, there are very few buffers
and salts that allow you to get data at those wavelengths (especially for
pharmaceutical samples), and for most purposes you are really only
interested in structural changes so the absolute accuracy of those predicted
secondary structure numbers is not that important anyway. Therefore I'm not
sure that in practice it really even makes any difference whether one
instrument works better than another in that region.
That's my two cents. 'Hope this helps.
John Philo
Alliance Protein Laboratories
www.ap-lab.com
-----Original Message-----
From: Association of Biomolecular Resource Facilities
[mailto:abrf-request@aecom.yu.edu]On Behalf Of Mary-ann.Gray@aventis.com
Sent: Friday, May 12, 2000 7:50 AM
To: Recipients of ABRF List
Subject: Advice on purchase of CD
Good morning everyone,
We are getting ready to purchase a CD and are considering the Jasco J-810. I
would like to know is anyone has any advice on what features are important
in the purchase of a CD. The primary aplication will be for examination of
protein stability through temperature and manufacturing changes. I have a
short review article ("CD Begins to Bloom", Analytical Chemistry News and
Features, August 1999) but am interested in current experience with this
instrument.
Thanks very much!
Mary-ann Gray
Mary-ann.Gray@aventis.com
(570) 839-4687
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