Diff. between intrinsic/extrinsic cell membrane proteins

[Dima Klenchin]

In article <bill-0211962041410001 at peacocks.demon.co.uk>, bill at peacocks.demon.co.uk wrote:
#PLease could someone tell me whether proteins found within cell membranes
#which penetrate the membrane but do not span the entire membrane are
#classed as intrinsic or extrinsic proteins; reference book s seem split
#over this.

This is just a matter of definition not worth to think about. 
IMO, it's better to use "functional" definition, one possible 
example of which is extraction with ~ 6 M urea. 
"True" membrane proteins (embedded in the membrane) cannot
be extracted since urea does not dissolve membrane bilyaer. 

- Dima