RE: Modification of tyrosine by the iodogen method

Chin, David T. (ChinD@missouri.edu)
Mon, 22 Nov 1999 14:53:12 -0600

Brett,
You can have mono- and di- iodotyrosine. Iodine is about the size of a
benzene ring -- It's big. To get one iodine per protein (assuming you
have at least one tyrosine), use 0.7 moles of KI per mole of protein. The
reaction is usually very efficient. If more iodine is use, you can get
quite of bit of di-iodinated protein or di-iodotyrosine. Paper
chromatography can be used to assay the amount of mono- vs. di- I-tyr.
Have a happy thanksgiving.

David

David T. Chin
Director, Protein Core Facility
Protein Chemistry and Expression
2-17 Agriculture Building
Univ. of Missouri - Columbia
Columbia, MO 65211-7170

SHIPPING AND ACTUAL LOCATION:
2-17 Agriculture Building (office)
2-31 Agriculture Building (Lab)

e-Mail: chind@missouri.edu <mailto:chind@missouri.edu>
web: http://www.biotech.missouri.edu/pc <http://www.biotech.missouri.edu/pc>

[ mailto:chind@missouri.edu <mailto:chind@missouri.edu> ]
Phone: 573-882-2027
Fax: 573-882-7105

-----Original Message-----
From: Brett Phinney [mailto:phinney@unity.ncsu.edu]
Sent: Sunday, November 21, 1999 2:18 PM
To: Recipients of ABRF List
Subject: Modification of tyrosine by the iodogen method

Hi, I was wondering if anyone knows of any rules concerning iodinating
tyrosine by the iodogen method. Specifically, will a tyrosine always be
iodinated multiple times if there is an excess of activated iodine over
tyrosine residues? Conversely, is it possible for a tyrosine to be modified
only once in the presence of excess activated iodine?


Thanks in advance for the info.


--------------------------
Brett Phinney
Department of Biochemistry
North Carolina State University
ph# 919-515-5786 fax# 919-515-2047