35-S labeled protein half life

Gopal Dasika dgk at zeus.ahabs.wisc.edu
Fri Nov 22 06:26:47 EST 1996

I am a little puzzled about sulphur turning into chlorine.
Could someone please clarify?

I was under the impression that exposure of [35-S] methionine to air
generates radioactive sulphur dioxide and hydrogen sulphide. 
Additionally, upon long term storage radiolysis of 35S-amino acids leads
to release of 35-S labelled volatile impurities.  Also the formation of
L-methionine sulfone may be a problem.


Gopal Dasika.

In article <199611161635.IAA41746 at itsa.ucsf.edu>, fauss at ITSA.UCSF.EDU
("Donald J. Fauss") wrote:

> Just to settle an argument, does anybody have an idea of what
> happens to 35-S methionine labeled proteins after the 35-S decays?
> I think the sulfur turns into chlorine and it's my guess that the
> proteins would be so drastically changed by this that they wouldn't
> be any good for things like immunodetection and such. My boss tries
> to get me to keep these labeled proteins forever but it seems to me
> that after they decay they aren't worth keeping. Anybody know more
> about this? If it matters, the proteins originally have a very high
> 35-S specific activity or as they say, "pretty hot".
> Don Fauss (fauss at itsa.ucsf.edu, http://members.aol.com/dfauss1)

Gopal Dasika

More information about the Cellbiol mailing list