Re: Misc. (Hg-S bond stability)

I.L. Rodionov (rodionov@fibkh.serpukhov.su)
Fri, 19 Nov 1999 00:38:07 +0300

Dear Norman,
It is very likely that several equivalents of any thiol reagent will
liberate cysteine SH- function from -Cys(HgX)-. Displacement of this
kind takes place during Acm-group cleavage when mercaptoethanol is used
in the final step. Note, that carbon-Hg bond is sensitive to this thiol
as well:
Nishio,H., Kimura,T. and Sakakibara,S. Side reaction in peptide
synthesis. Modification of tryptophan during treatment with mercury(II)
acetate/2-mercaptoethanol in aqueous acetic acid.
Tetrahedron Lett, 1994, v.35(8), pp.1239-1242.

Regards,
Igor
------------------------------------------------
Igor L. Rodionov
Laboratory of Peptide Chemistry
Branch of Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry
Science Avenue 6
Pushchino, Moscow Region
142292, Russian Federation
E-mail: <rodionov@fibkh.serpukhov.su>
Fax: (0967)-79-05-27
Phones: (0967) 73 54 42; private: (0967) 73 58 26
http://www.fibkh.serpukhov.su/

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Original message:

I am labelling viral cyteines with heavy metal clusters and I know that
the mercury-sulfur bond is very strong (though I have seen the Hg
"disappear" in ES-MS).

My question is, how likely is it that a Hg cluster, such as
tetrakis(acetoxymercuri)methane, bound to cysteine would be displaced
from the sulfur by a reagent such as 2-aminoethanethiol or
penicillamine.

Norman