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Phosphatidate phosphohydrolase catalyzes the hydrolysis of ceramide 1-phosphate, lysophosphatidate, and sphingosine 1-phosphate.

Authors: Waggoner, D W  Gómez-Muñoz, A  Dewald, J  Brindley, D N 
Citation: Waggoner DW, etal., J Biol Chem. 1996 Jul 12;271(28):16506-9. doi: 10.1074/jbc.271.28.16506.
Pubmed: (View Article at PubMed) PMID:8663293
DOI: Full-text: DOI:10.1074/jbc.271.28.16506

A Mg2+-independent phosphatidate phosphohydrolase was purified from rat liver plasma membranes in two distinct forms, an anionic protein and a cationic protein. Both forms of the enzyme dephosphorylated phosphatidate, ceramide 1-phosphate, lysophosphatidate, and sphingosine 1-phosphate. When assayed at a constant molar ratio of lipid to Triton X-100 of 1:500, the apparent Km values of the anionic phosphohydrolase for the lipid substrates was 3.5, 1.9, 0.4, and 4.0 microM, respectively. The relative catalytic efficiency of the enzyme for phosphatidate, ceramide 1-phosphate, lysophosphatidate, and sphingosine 1-phosphate was 0.16, 0.14, 0.48, and 0.04 liter (min x mg)-1, respectively. The hydrolysis of phosphatidate was inhibited competitively by ceramide 1-phosphate, lysophosphatidate, and sphingosine 1-phosphate. The Ki(app) values were 5.5, 5.9, and 4.0 microM, respectively. The hydrolysis of phosphatidate by the phosphohydrolase conformed to a surface dilution kinetic model. It is concluded that the enzyme is a lipid phosphomonoesterase that could modify the balance of phosphatidate, ceramide 1-phosphate, lysophosphatidate, and sphingosine 1-phosphate relative to diacylglycerol, ceramide, monoacylglycerol, and sphingosine, respectively. The enzyme could thus play an important role in regulating cell activation and signal transduction.

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RGD ID: 15090855
Created: 2019-12-20
Species: All species
Last Modified: 2019-12-20
Status: ACTIVE



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