Effects of pH on the binding of hematoporphyrin derivative to monolayer and bilayer membranes.
The effects of pH on the binding of hematoporphyrin derivative (HpD) to monolayer and bilayer membranes have been studied. Absorption spectra of HpD bound to phosphatidylcholine (PC) liposomes indicate that there is greater binding of HpD to lipid films at acidic, tumoricidal pH conditions than at normal tissue pH. These results were found to correlate with surface pressure measurements of monolayer films formed under similar conditions. Surface potential measurements in conjunction with surface pressure measurements from monolayer films suggest that at low pH (i.e. less than or equal to 6.6) porphyrin intercalates within the lipid film to reach relatively high concentrations, while at higher pH (i.e. greater than or equal to 7.4) the porphyrin preferably adsorbs to the lipid film at the monolayer/water interface.
Rich
M R
MR
Department of Biology, New York University, NY 10003.
Ferraro
G
G
Brody
S S
SS
D017324:Hematoporphyrin Derivative; D006415:Hematoporphyrins / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008051:Lipid Bilayers / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry; D008564:Membrane Potentials; D010713:Phosphatidylcholines / Q000737:chemistry; D013053:Spectrophotometry
D006415:Hematoporphyrins; D008051:Lipid Bilayers; D008081:Liposomes; D010713:Phosphatidylcholines; D017324:Hematoporphyrin Derivative