Evaluation of inhibitory actions of flavonols and related substances on lysophospholipase d activity of serum autotaxin by a convenient assay using a chromogenic substrate.
Overproduction of lysophosphatidic acid (LPA) by lysophospholipase D/autotaxin (lysoPLD/ATX) is postulated to be involved in the promotion of cancer and atherosclerosis. A lysoPLD inhibitor may be utilized to ameliorate the LPA-related pathological conditions. In this study, a new assay was devised to quantify p-nitrophenol from hydrolysis of chromogenic substrate by serum lysoPLD without tedious lipid extraction procedures. Flavonols, phenolic acids, free fatty acids, and N-acyltyrosines inhibited lysoPLD activity in a micromolar range. They were classified into competitive, noncompetitive, or mixed type inhibitors. The results show that the low hydrophobicity of an inhibitor is a critical factor in its preference for the binding to a noncatalytic binding site over a catalytic binding site. Considering its reported bioavailability and the low dependency of its inhibitory activity on serum dilution, flavonol is likely to be a more effective lysoPLD inhibitor in human blood circulation in vivo than the other inhibitors including LPA.
Ueda
Kaori
K
Institute of Health Biosciences, University of Tokushima Graduate School, 1-78-1 Shomachi, Tokushima 770-8505, Japan.
Yoshihara
Masanori
M
Nakao
Michiyasu
M
Tanaka
Tamotsu
T
Sano
Shigeki
S
Fukuzawa
Kenji
K
Tokumura
Akira
A
D001665:Binding Sites; D001667:Binding, Competitive; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D044948:Flavonols / Q000494:pharmacology*; D006801:Humans; D009097:Multienzyme Complexes / Q000097:blood*; D043264:Phosphodiesterase I / Q000097:blood*; D010727:Phosphoric Diester Hydrolases / Q000097:blood*; D011755:Pyrophosphatases / Q000097:blood*; D011994:Recombinant Proteins; D000099189:Lysophospholipase D
D004791:Enzyme Inhibitors; D044948:Flavonols; D009097:Multienzyme Complexes; D043264:Phosphodiesterase I; D010727:Phosphoric Diester Hydrolases; D011755:Pyrophosphatases; D011994:Recombinant Proteins; D000099189:Lysophospholipase D