Charcoal surface-assisted catalysis of intramolecular disulfide bond
formation in peptides.
Volkmer-Engert R, Landgraf C, Schneider-Mergener J
Institut fur Medizinische Immunologie, Universitatsklinikum Charite,
Humboldt-Universitat zu Berlin, Germany.
A mild and highly efficient method for intramolecular disulfide bond
formation in peptides mediated by charcoal has been
developed. Completion of the charcoal-assisted catalysis of disulfide bond
formation took less than 6 h, testing a series of
peptides with ring sizes varying from 2 to 17 amino acids. Kinetic studies
revealed that the formation of small and large
intramolecular disulfide cycles especially was accelerated significantly by
the aid of charcoal as compared with dimethyl
sulfoxide- and air-mediated cyclization. Oxygen adsorbed onto the charcoal
surface is a prerequisite for disulfide bond
formation. Thermodynamic studies showed that cyclization is accelerated by
reduction of entropy of the peptides, most likely
because of transient adsorption to the charcoal surface, thus resulting in a
lower activation energy.
PMID: 9606016, UI: 98267053
Richard F. Cook wrote:
> Dear ABRFers,
>
> I'm looking for the latest and greatest reference on how to form cyclic
> peptides through cysteine SH groups when there are are more than two
> cysteines present.
>
> I was wondering if the use of ACM to block the unwanted Cys residue,
> followed by cyclization, followed by mecury acetate removal of the ACM is
> still in vogue or if there is a better protecting group or strategy
> available.
>
> Thanks in advance,
>
> Dick Cook
-- Matteo Villain E-mail : villain@uab.edu Research Associate Phone : 205 934 3032 University of Alabama Fax : 205 934 1446 Birmingham 35294, USA