Aluminum fluoride inhibition of cabbage phospholipase D by a phosphate‐mimicking mechanism

FEBS Letters

Fleming, Norman¹  Li, Liang¹ 

[1] Department of Oral Biology, University of Manitoba, 780 Bannatyne Avenue, Winnipeg, Man. R3E 0W2, Canada

关键词: Phospholipase D;    Aluminum fluoride;    Cabbage;   

DOI  :  10.1016/S0014-5793(99)01414-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Aluminum fluoride (AlF₄ ⁻) inhibited phospholipase D (PLD) purified from cabbage in both PIP₂-dependent and PIP₂-independent assays, consistent with its previously observed effect on mammalian PLD. The possibility that AlF₄ ⁻ may exert this effect through its known phosphate-mimicking property was examined. Inorganic phosphate, as well as two phosphate analogs, beryllium fluoride and orthovanadate, also inhibited cabbage PLD. Enzyme kinetic studies confirmed that PLD followed Hill kinetics, characteristic for allosteric enzymes, with an apparent Hill coefficient (n _app) of 3.8, indicating positive cooperativity among multiple substrate-binding sites and suggesting possible functional oligomerization of the enzyme. AlF₄ ⁻ modification of PLD kinetics was consistent with a competitive mode of enzyme inhibition. It is therefore proposed that AlF₄ ⁻, and other phosphate analogs, inhibits plant PLD by competing with a substrate phosphate group for a substrate-binding site, thereby preventing the formation of an enzyme-phosphatidyl intermediate. This may be a conserved feature of PLD superfamily enzymes.

【 授权许可】

Unknown