SDS debate

[Nick Theodorakis]

In <Pine.SGI.3.96.1010809213727.95373A-100000 at ccmb.ap.nic.in>, 
Malay wrote:
>
>> Proteins vary, of course, but the tendency will be for SDS to "stretch out" 
>> the protein chain, so your colleague is closer to being correct. 
Consider 
>> that SDS is highly charged at neutral pH, so that when a protein is 
>> slathered in it the charges tend to want to repel each other so the chain 
>> unfolds. 
>
>I don't really think so. SDS and protein interaction is not on the basis
>of charge but hydrophobicity. SDS actually partially unfolds a proteins it
>acts more like a solvent to keep the protein in unfolded state and
>preventing aggregation, rather than acting as denaturant per se.
[...]


I didn't say that SDS interacted with proteins by charge; I said that it was 
charged. It's a given that detergents interact hydrophobically. But  ionic 
detergents have consequences beyond simple hydrophobic interactions 
because of their charge.

Nick

-- 
Nick Theodorakis
nicholas_theodorakis at urmc.rochester.edu