[RASMB] MALLS

[Joel Mackay]

Hi all,
We are currently considering the purchase of a multiangle laser light 
scattering instrument for getting a snapshot of protein molecular weight - 
we intend to hook up to one of our chromatography systems. [Of course it 
isn't intended as a replacement for our venerable XLA... - we just thought 
it would be handy for getting a feel for molecular weight during the 
chromatography stage].

I must confess i haven't really got any experience with this technology, 
but i thought at least some of the people in this forum might, and i hoped 
i could get answers to a couple of questions...

1. What is the general feeling about this method for looking at proteins - 
i know quite a few people use it in chemical polymer applications, but 
their problems are often a bit different (branching etc), and their 
polymers are often much bigger. Is it useful? We are not so interested in 
shape (so are not bothering with dynamic light scattering) - more in 
molecular mass.

2. What sort of masses can be measured with confidence on an instrument 
like the mini-Dawn from Wyatt - we often deal with proteins that are ~5-10 kDa.

3. Wyatt seems to be the major player in the field, but i have been getting 
info from Precision Detectors as well. Does anyone have any comments 
(printable!) to make about either manufacturer's instruments etc?

4. Do people tend to use a refractometer to measure refractive indices, or 
use calculated values?

Any comments most appreciated!

cheers
joel


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Dr Joel Mackay
Senior Lecturer
School of Molecular and Microbial Biosciences
Building G08
University of Sydney,
Sydney, NSW 2006
Australia
ph +61-2-9351-3906
fax +61-2-9351-4726
WWW: http://www.mmb.usyd.edu.au/mackay/
Sydney Protein Group Website:
http://www.mmb.usyd.edu.au/spg/
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