Apyrase inhibitors affect pollen growth
Discovery Lab Lecture
February 7, 2008
Apyrase inhibitors were discovered in a
screen of 9,000 small organic molecules
Assay tested whether randomly selected
organic compounds could block the ability of
potato apyrase to remove phosphates from
Only 17 compounds were found to be
These inhibitors differed in their relative
These were the first compounds found to be
very effective inhibitors of apyrase activity
Inhibitors NGXT 191, NGXT 1913 and #4
differ in their ability to inhibit other phosphatases
Table S1. Relative Inhibitory Activity of Apyrase Inhibitors 1, 4, and 13 toward Potato
Apyrase , Acid Phosphatase and Alkaline Phosphatases
Inhibitor Potato Apyrase Acid Phosphatase Alkaline Phosphatase
NGXT 191 89 0 83
NGXT 1913 100 8 27
# 4 73 86 15
Numbers given in % inhibition. Data taken from Windsor, B. (2000). Establishing a role for
ecto-phosphatase in drug resistance. Ph.D. dissertation, The University of Texas at Austin.
Details of assay are given in the dissertation and in: Windsor, J.B., Thomas, C., Hurley, L., S. J.
Roux, S.J., and Lloyd, A.M. (2002). An automated colorimetric screen for apyrase inhibitors.
Biotechniques 33, 1024-1030.
NGXT 191 and Inhibitor #4 simultaneously
inhibit pollen tube growth and raise the [eATP]
Sample results from last week
Low: 0.32 vs 0.46; 0.03 vs 0.12;
0.36 vs. 0.15; 2.21 vs. 0.56
High: 0.14 vs. 0.15; 0.15 vs. 0.15;
0.08 vs. 0.07; 0.07 vs. 0.01
Review data from last week √
Training on how to make bar graphs (for next week’s
presentations and reports).
Transfer samples planted last week to test media
(Round 1 of experiments):
> low (30 mM) or high (150 mM) GTPS
> inhibitor #2 (various concentrations)
> DPI (5 or 10 mM) + 30 mM ADPS
Then measure effects on root hair growth
Those giving oral reports need to load their
presentations between 2:00 and 2:25 PM on
Thursday (or send file to Dr. Clark by e-mail &
ask him to load it). NOTE: If you have new
Vista operating system, save your .ppt in old
Those giving written reports, send your file to
Dr. Clark by 2:15 on Thursday, and bring a
hard copy to class.