US EPA

8323477 

Journal Article 

Synthetic catalytic pores 

Sakai, N; Sordé, N; Matile, S; , 

2003 

Yes 

Journal of the American Chemical Society
ISSN: 0002-7863
EISSN: 1520-5126 

125 

26 

7776-7777 

English 

12822976 

10.1021/ja029845w 

Catalytic activity of a synthetic multifunctional pore is studied in large unilamellar vesicles under conditions where substrate and synthetic catalytic pore (SCP) approach the membrane either from the same side (cis catalysis) or from opposite sides (trans catalysis). A synthetic supramolecular rigid-rod beta-barrel with excellent ion channel characteristics is identified as SCP using 8-acetoxypyrene-1,3,6-trisulfonate (AcPTS) as model substrate. The key finding is that application of supportive membrane potentials increases the initial velocity of AcPTS esterolysis (v0). This results in an increase of Vmax beyond experimental error (+30%), whereas KM increases less significantly. Long-range electrostatic steering by the membrane potential, possibly guiding substrates into the transmembrane catalyst and, more importantly, accelerating product release (foff = 1.3) is discussed as one possible explanation of this global reduction of catalyst saturation. Control experiments show, inter alia, that similarly strong changes do not occur with opposing membrane potentials.