B. Maisterrena et al., ACTIVE-TRANSPORT OF GLYCEROL-3-PHOSPHATE WITH ARTIFICIAL ENZYME MEMBRANES - A NEW KINETIC-MODEL FOR ACTIVE-TRANSPORT PROCESSES, Journal of membrane science, 134(1), 1997, pp. 85-99
An approach to the mechanism which may govern translocation and active
transport system is presented. Two artificial enzyme membranes with i
mmobilized kinase and immobilized phosphatase, respectively, were used
close together to separate two unequal compartments of a specially de
signed diffusion cell in order to mimic solute active transport. Exper
iments were conducted and both translocation and active transport of g
lycerol-3-phosphate were obtained. The theoretical analysis of this ac
tive transport-like phenomenon, which underlines the key role played b
y the charge distribution on the membrane and the diffusion layers exi
sting close to the membrane-bound enzymes is presented and is in good
agreement with the experimental data. Our results mainly demonstrate t
hat under specific conditions, the association of kinase and phosphata
se activities on both parts of a porous membrane functions as an enzym
ic pump which performs active transport. Such results may be of genera
l significance and lead us to suggest that a carrier could be substitu
ted by two catalytic activities bound on both parts of a structure of
channel type and catalysing two opposite reactions in diffusion layers
.