Seminar in Organic & Biophysical Chemistry
Ben-Gurion University of the Negev
Department of Chemistry
Sunday, May 17, 2015
Time 16:00
Bldg. 37 Room 202
Maya Refua
(MSc Lecture)
Under the supervision of Prof. Ashraf Brik
Department of chemistry, Ben Gurion University in the Negev, Beer-Sheva , Israel
Development of HTS Assay for DUBs Using Expeditious
Chemical Synthesis of Ubiquintnated Peptides
Deubiquitiananses (DUBs) are a family of enzyme that catalyzes the hydrolysis reaction
between the ubiquitin and the target protein. DUBs are involved in wide verity of regulatory
processes and have an important role in various diseases, which make them a potential
therapeutic target.1 Thus, an efficient HTS assay is needed for studying the role of DUBs and
for finding inhibitors for pharmaceutical needs. In the recent years several HTS assay were
developed including the HTS assay that was design by our group, where a ubiquitinated
peptide was labeled with a quenching pair and upon cleavage of the isopeptide bond by
DUBs shows increase in the florescence signal.2 While using our HTS assay we were able to
find inhibitors against UCH-L3 and USP2,3 this can serve as a motivation for further
screening of large libraries of compounds against different kinds of DUBs. However, in order
to screen large number of compounds we should aim to work with the most efficient
substrate. In my talk, I will present a new approach to synthesize ubiquitinated peptides in a
rapid manner that enabled us to further optimize our HTS assay and its kinetic parameters.
1. Reyes-Turcu, F. E.; Wilkinson, K. D. Chem. Rev. 2009, 109, 1495–1508.
2. S. Ohayon, L. Spasser, A. Aharoni, A. Brik, J. Am. Chem. Soc., 2012, 134, 3281-3289
3. S. Ohayon, M. Refua, A. Hendler A. Aharoni, A. Brik, Angew.Chem., 2015, 127, 609-613
Alexander Frenklah
(MSc Lecture)
Under the supervision of Prof. Gabriel Lemcoff
Department of chemistry, Ben Gurion University in the Negev, Beer-Sheva , Israel
Selective Hydrogenation of a Nitro Compound to a
Hydroxylamine Compound
The catalytic semi-hydrogenation of nitro aryl compounds to give aryl hydroxyl amines is
an atom-efficient process. In contrast to stoichiometric reduction methods, such as the
selective reduction of nitro aryl compounds with zinc dust and ammonium chloride, only one
equivalent of water is produced as byproduct in catalytic hydrogenation reactions.
The use of heterogeneous instead of homogenous catalysts in organic processes may allow
easier catalyst recovery and might have advantages in the handling of the catalyst, as
heterogeneous catalysts commonly possess longer service life.
A study was performed in ADAMA-Makhteshim in cooperation with an outsourcing
research company, where the catalytic semi-hydrogenation of a nitro aryl compound was
explored. This reaction represents a key step in the synthesis of a crop protection product.
The current presentation will summarize this study including scale-up of the developed
process to production scale while meeting various stringent requirements, such as
environmental aspects, safety, reproducibility, and cost efficiency.