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Figure 3 | Lipids in Health and Disease

Figure 3

From: L-histidine inhibits production of lysophosphatidic acid by the tumor-associated cytokine, autotaxin

Figure 3

Histidine inhibition of ATX enzyme activities and sensitivity to zinc. For these reactions, 1 mM LPC served as substrate for LPLD activity and 1 mM pNp-TMP as substrate for 5'-nucleotide PDE activity; approximately 6 pmoles of ATX was added to each reaction. A.) Product was measured in the presence of variable concentrations of L-histidine. Data are shown as Mean ± SEM. The two reactions were not significantly different from each other. B.) Different metal cations (0.5 mM) were compared for their capacity to abrogate L-histidine (10 mM) inhibition of enzymatic reactions. C.) Effect of Zn++ on LPC- and ATX-stimulated motility. Utilizing A2058 cells as responders and either ATX or 25 nM LPA as chemoattractant, 20 mM histidine or 0.25 mM ZnSO4 or both were added to the bottom wells throughout the motility assay. Data are shown as Mean ± SEM. Means were compared with ANOVA/Tukey's post-test (GraphPad Prism, San Diego, CA). For B), comparisons were between histidine-treated vs. the equivalent untreated reactions with * (p < 0.001). For C), comparisons were as follows: * (p < 0.001) vs. ATX alone, ** (p < 0.001) vs. ATX + His, # (p < 0.01) vs. ATX alone.

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