Skip to main content
. Author manuscript; available in PMC: 2015 Aug 1.
Published in final edited form as: Exp Cell Res. 2014 Jun 9;326(1):136–142. doi: 10.1016/j.yexcr.2014.05.025

Figure 1.

Figure 1

Uric acid inhibition of cell bound CD26/DPPIV activity is competitive and requires cellular uptake of uric acid. Human recombinant CD26/DPPIV is not inhibited by uric acid, allantoin, or 6-aminouracil HUVEC were cultured, collected by trypsinization and then assayed for CD26/DPPIV activity. (A) HUVEC were incubated with the indicated concentration of uric acid and 60 µM Gly-Pro-AMC. Cleavage was recorded with a 360 nm excitation filter and a 460 nm emission filter. *P<0.0025 compared to 0 mg/dl uric acid. (n = 6. Error bars ± 1 s.d.) (B) HUVEC were incubated with the indicated concentration of Gly-Pro-AMC in the presence (grey bars) and absence (open bars) of 15 mg/dl uric acid. Each point is in triplicate shown ± standard deviation. *P < 0.05 compared to no uric acid. (C) 60 µM Gly-Pro-AMC was added to HUVEC in the presence or absence of 15 mg/dl of uric acid and/or probenecid (1 mM) as indicated. * P = 0.00003. (n = 5. Error bars ± 1 s.d.). (D) Uric acid (15 mg/dl) was added to human recombinant CD26/DPPIV (rCD26/DPPIV) (0.0625 ng/µl). All replicates for the 4 times the experiment has been repeated is shown (n = 9. Error bars ± 1 s.d.).