Tuning Cerium(IV)‐Assisted Hydrolysis of Phosphatidylcholine Liposomes under Mildly Acidic and Neutral Conditions |
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Authors: | Dr. Dominique E. Williams Kanchan Basnet Prof. Kathryn B. Grant |
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Affiliation: | Department of Chemistry, Georgia State University, P.O. Box 3965, Atlanta, GA 30302‐3965 (USA) |
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Abstract: | With the goal of designing a lysosomal phospholipase mimic, we optimized experimental variables to enhance CeIV‐assisted hydrolysis of phosphatidylcholine (PC) liposomes. Our best result was obtained with the chelating agent bis–tris propane (BTP). Similar to the hydrolytic enzyme, CeIV‐assisted hydrolysis of PC phosphate ester bonds was higher at lysosomal pH (~4.8) compared to pH 7.2. In the presence of BTP, the average cleavage yield at ~pH 4.8 and 37 °C was: 67±1 %, 5.7‐fold higher than at ~pH 7.2 and roughly equivalent to the percent of phospholipid found on the metal‐accessible exo leaflet of small liposomes. No CeIV precipitation was observed. When BTP was absent, there was significant turbidity, and the amount of cleavage at ~pH 4.8 (69±1 %) was 2.1‐fold higher than the yield obtained at ~pH 7.2. Our results show that BTP generates homogenous solutions of CeIV that hydrolyze phosphatidylcholine with enhanced selectivity for lysosomal pH. |
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Keywords: | hydrolysis lanthanides liposomes lysosomes phosphate ester |
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