1.Selective and reversible thiol-pegylation, an effective approach for purification and characterization of five fully active ficin (iso)forms from Ficus carica latex.
Azarkan M1, Matagne A, Wattiez R, Bolle L, Vandenameele J, Baeyens-Volant D. Phytochemistry. 2011 Oct;72(14-15):1718-31. doi: 10.1016/j.phytochem.2011.05.009. Epub 2011 Jun 12.
The latex of Ficus carica constitutes an important source of many proteolytic components known under the general term of ficin (EC 3.4.22.3) which belongs to the cysteine proteases of the papain family. So far, no data on the purification and characterization of individual forms of these proteases are available. An effective strategy was used to fractionate and purify to homogeneity five ficin forms, designated A, B, C, D1 and D2 according to their sequence of elution from a cation-exchange chromatographic support. Following rapid fractionation on a SP-Sepharose Fast Flow column, the different ficin forms were chemically modified by a specific and reversible monomethoxypolyethylene glycol (mPEG) reagent. In comparison with their un-derivatized counterparts, the mPEG-protein derivatives behaved differently on the ion-exchanger, allowing us for the first time to obtain five highly purified ficin molecular species titrating 1mol of thiol group per mole of enzyme.
2.High yielding selective access to spirocyclopropanated 5-oxopiperazine-2-carboxylates and 1,4-diazepane-2,5-diones from methyl 2-chloro-2-cyclopropylideneacetate.
Limbach M1, Korotkov VS, Es-Sayed M, de Meijere A. Org Biomol Chem. 2008 Oct 21;6(20):3816-22. doi: 10.1039/b809174a. Epub 2008 Aug 13.
The 2-spirocyclopropanated methyl 5-oxopiperazine-2-carboxylate and the 3-spirocyclopropanated 6-chloro-1,4-diazepane-2,5-dione could both be prepared at choice in 93 and 88% yield, respectively, from methyl 2-chloro-2-cyclopropylideneacetate () in a sequence of Michael addition of 3-benzyloxypropylamine, peptide coupling with N-Boc-glycine, Boc-group removal and cyclization. Transformation of the benzyloxypropyl side chain, peptide coupling with N-Boc-(S)-asparagine, deprotection and repeated cyclization led to the octahydro[2H]pyrazino[1,2-a]pyrazinetrione scaffold containing a rigidified mimic of a tripeptide with a DGR motif. The overall yield of after deprotection of (a total of 13 steps in 8 distinct operations) was 30%.
3.Efficient construction of PET/fluorescence probe based on sarcophagine cage: an opportunity to integrate diagnosis with treatment.
Liu S1, Li D, Huang CW, Yap LP, Park R, Shan H, Li Z, Conti PS. Mol Imaging Biol. 2012 Dec;14(6):718-24. doi: 10.1007/s11307-012-0557-z.
PURPOSE: Due to the shortage of established platforms/methods for multimodality probe construction, in this study, we developed a heterofunctional chelator, BaAn(Boc)Sar, from sarcophagine cage as a general platform for dual-modality probe construction.
4.Application of carbodiimide mediated Lossen rearrangement for the synthesis of alpha-ureidopeptides and peptidyl ureas employing N-urethane alpha-amino/peptidyl hydroxamic acids.
Narendra N1, Chennakrishnareddy G, Sureshbabu VV. Org Biomol Chem. 2009 Sep 7;7(17):3520-6. doi: 10.1039/b905790k. Epub 2009 Jul 7.
Application of the Lossen rearrangement to the synthesis of N-urethane protected alpha-peptidyl ureas and ureidopeptides is reported. The carbodiimide mediated rearrangement of N-Boc/Z/Fmoc protected alpha-amino/peptide hydroxamic acids into isocyanates and coupling of the latter with the amino acid esters/peptide esters have been accomplished in a single-pot to obtain good yields of urea products. Synthesis of the ureidoalanine derivatives via the hydroxamate derivatives of N-protected aspartic acid has also been carried out using the same procedure.
![L-Glutamic acid-[1,2-13C2]](https://resource.bocsci.com/structure/l-glutamicacid-%5B1%2C2-13c2%5D.gif)
