P. Clapes et al., Highly concentrated water-in-oil emulsions as novel reaction media for protease-catalysed kinetically controlled peptide synthesis, J CHEM S P2, (8), 2001, pp. 1394-1399
Citations number
57
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2
High-internal-phase-ratio-emulsions (HIPREs) or gel emulsions, formulated w
ith a large amount of water (80.0-99.5% w/w), were investigated as reaction
media for alpha -chymotrypsin-catalysed peptide synthesis under kinetic co
ntrol using Ac-L-Phe-OEt and H-L-Leu-NH2 as model substrates. Both the init
ial reaction rate and dipeptide yield were examined as a function of the st
ructure of the non-ionic polyoxyethylene alkyl ether type surfactant, alkyl
chain length of the oil component, temperature and aqueous buffer content.
Dipeptide yields of 70% were achieved in gel emulsions formulated with 90%
w/w aqueous buffer. In these systems, the reaction performance was found t
o be independent of the gel emulsion system (i.e. surfactant and oil) and t
herefore of the water-oil interfacial tension. Interestingly, alpha -chymot
rypsin showed superactivity at surfactant concentrations ranging between 0.
2 and 0.8% w/w, that is, at 99.5and 98.0% w/w water content, respectively.
Furthermore, high dipeptide yields (90-94%) were achieved in the gel emulsi
ons studied at very high substrate concentrations and thus with undissolved
reactants. Under these conditions, examples of alpha -chymotrypsin-catalys
ed dipeptide synthesis on an analytical and preparative scale were conducte
d.