I used Iodogen for many years to iodinate peptides successfully. My
understanding is that you will always get a mixture of mono- and
di-iodotyrosine derivatives. I believe that the inductive effects of the
first substitution actually enhance the rate of the 2nd substitution, but
you also get competing steric hinderance, so it's almost impossible to
control to either mono or di substitution.
Hope this helps!
Roger
At 15:18 21/11/99 -0500, you wrote:
>abrf@aecom.yu.edu
------------------------------------------------------------
Roger Murphy, Ph.D.
Biological Production Facility
Ludwig Institute for Cancer Research
Austin & Repatriation Medical Centre
Studley Road,
Heidelberg, Vic. 3084
Australia.
Tel 61-3-94965463
Fax 61-3-94965436
Email Roger.Murphy@Ludwig.edu.au