Fachbereich Biologie, Universität Kaiserslautern, Postfach 3049, D-6750 Kaiserslautern, Federal Republic of Germany.
Plant Physiol. 1986 Jan;80(1):7-13. doi: 10.1104/pp.80.1.7.
The activity of 1,3-beta-d-glucan synthase assayed in the presence of digitonin in a microsomal preparation from suspension-cultured cells of Glycine max can be fully inhibited by unsaturated fatty acids, trienoic acids being most effective. Lysophosphatidylcholine, platelet-activating factor, acylcarnitine, and Echinocandin B can also fully inhibit the enzyme. Inhibition is observed both when the enzyme is activated by Ca(2+) or by trypsinization. At low amounts some of the substances can also cause stimulation. These effects all may result from a displacement of certain endogenous phospholipids necessary for optimal activity of the 1,3-beta-d-glucan synthase.In the absence of digitonin the enzyme activity is greatly stimulated by lysophosphatidylcholine, platelet-activating factor, acylcarnitine, and Echinocandin B within a certain concentration range, presumably by rendering the microsomal vesicles permeable to the substrate and Ca(2+). Dibucaine does not cause such an effect.Acylcarnitine and Echinocandin B at low concentrations can induce callose synthesis in vivo; this effect is enhanced by chitosan. At higher concentrations the two substances and polyunsaturated fatty acids cause severe electrolyte leakage. The effects are discussed in regard to the induction of callose synthesis by enforced Ca(2+) influx, and its modulation by membrane lipids.
在悬浮培养的 Glycine max 细胞的微粒体制剂中，在胆酸钠存在的情况下测定的 1,3-β-D-葡聚糖合酶的活性可被不饱和脂肪酸完全抑制，三烯酸的抑制作用最为有效。溶血磷脂胆碱、血小板激活因子、酰基辅酶 A 和棘白菌素 B 也可完全抑制该酶。当酶被 Ca2+或胰蛋白酶激活时均可观察到抑制作用。在低浓度下，一些物质也可以引起刺激。这些影响可能都是由于某些内源性磷脂的置换所致，这些磷脂对于 1,3-β-D-葡聚糖合酶的最佳活性是必需的。
在没有胆酸钠的情况下，在一定浓度范围内，溶血磷脂胆碱、血小板激活因子、酰基辅酶 A 和棘白菌素 B 可极大地刺激酶活性，推测这是通过使微粒体囊泡对底物和 Ca2+通透而实现的。二甲卡因不会产生这种效果。
在低浓度下，酰基辅酶 A 和棘白菌素 B 可在体内诱导几丁质合成；壳聚糖可增强这种作用。在较高浓度下，这两种物质和多不饱和脂肪酸会导致严重的电解质渗漏。这些影响与强制 Ca2+内流诱导几丁质合成及其通过膜脂质的调节有关。
