Choi JY, Surovtseva YV, Van Sickle SM, Kumpf J, Bunz UHF, Ben Mamoun C, Voelker DR. A novel fluorescence assay for measuring phosphatidylserine decarboxylase catalysis.
J Biol Chem 2017;
293:1493-1503. [PMID:
29247006 DOI:
10.1074/jbc.ra117.000525]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 12/07/2017] [Indexed: 11/06/2022] Open
Abstract
Phosphatidylserine decarboxylases (PSDs) are central enzymes in phospholipid metabolism that produce phosphatidylethanolamine (PE) in bacteria, protists, plants, and animals. We developed a fluorescence-based assay for selectively monitoring production of PE in reactions using a maltose-binding protein fusion with Plasmodium knowlesi PSD (MBP-His6-Δ34PkPSD) as the enzyme. The PE detection by fluorescence (λex = 403 nm, λem = 508 nm) occurred after the lipid reacted with a water-soluble distyrylbenzene-bis-aldehyde (DSB-3), and provided strong discrimination against the phosphatidylserine substrate. The reaction conditions were optimized for enzyme, substrate, product, and DSB-3 concentrations with the purified enzyme and also tested with crude extracts and membrane fractions from bacteria and yeast. The assay is readily amenable to application in 96- and 384-well microtiter plates and should prove useful for high-throughput screening for inhibitors of PSD enzymes across diverse phyla.
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