From: Greg Ralston <gregr@atp.biochem.usyd.edu.au>
  To  : demeler@bioc02.uthscsa.edu
  Date: Tue, 11 Jun 1996 10:48:46 +1000

Re: monomer-dimer systems

Hi, Borries,

Beta lactoglobulin B satisfies some (most?) of your requirements:

It dimerises cleanly;
The K value is accessible in UV and is pH- and ionic strength-dependent;
Its monomer MW is a little low: 18,200, but not too far off;
It is well-characterised, stable and the association behaviour is robust;
It is reasonably cheap: Sigma sell it, but it ain't that pure. We had trouble 
with theirs, so we found our own cow and made our own. The preparation is 
straightforward; finding a homozygous cow is more of a problem. There is another
common lactoglobulin (the A variant), in most dairy herds, that associates 
indefinitely beyond the dimer. I think there must be some of that in the Sigma 
prep.


See Joss and Ralston, Analytical Biochem. 236, 20-26 (1996)

Cheers,

Greg Ralston




Greg Ralston
(Associate Professor)

Phone (61 2) 351 3906
Fax   (61 2) 351 4726

e-mail: G.Ralston@biochem.usyd.edu.au 

Department of Biochemistry
University of Sydney
Sydney, NSW, 2006
Australia