Activation of human spleen glucocerebrosidases by monoacylglycol sulfates and diacylglycerol sulfates.
Activation of human spleen glucocerebrosidases by monoacylglycol sulfates and diacylglycerol sulfates.
复制标题
单酰基乙二醇硫酸盐和二酰基甘油硫酸盐激活人脾葡萄糖脑苷脂酶。
DOI：
10.1016/0003-9861(88)90197-x
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发表时间：
1988
影响因子：
3.9
通讯作者：
Glew,RH
中科院分区：
文献类型：
--
作者：
Gonzales,ML;Basu,A;deHaas,GH;Dijkman,R;vanOort,MG;Okolo,AA;Glew,RH
对人脾葡萄糖脑苷脂酶的酸性脂质需求的研究扩展到包括两个新系列的酸性脂质，即单酰基乙二醇硫酸酯和二酰基甘油硫酸酯。用胆酸钠和正丁醇提取溶酶体葡萄糖脑苷脂酶，使其β-葡萄糖苷酶活性依赖于外源性脂质。用壬酰乙二醇硫酸盐（NGS）和二庚酰甘油硫酸盐（DHGS）获得对照葡糖脑苷脂酶的最大再活化。然而，这些脂质的作用明显依赖于试验培养基中使用的缓冲液的性质;具体而言，0.2 m柠檬酸-磷酸钠（pH 5.5）在允许这些脂质重新激活葡萄糖脑苷脂酶方面比0.2 m乙酸钠（pH 5.5）有效得多。相比之下，葡萄糖脑苷脂酶的显着激活磷脂酰丝氨酸和半乳糖苷3-硫酸酯（硫苷脂），这是在乙酸钠缓冲液中实现的柠檬酸盐或磷酸根离子完全抑制。NGS和DHGS对对照葡萄糖脑苷脂酶动力学参数的影响是使底物4-甲基伞形酮基-β-d-葡萄糖苷的Km从5.5mm降低到约2 mm（在柠檬酸钠-磷酸盐缓冲液中），并显著增加Vmax。此外，与DHGS，实现了显着的激活浓度低于脂质的临界胶束浓度。没有一个单酰基乙二醇或二酰基甘油硫酸酯能够刺激1型（阿什肯纳兹-犹太）或2型戈谢病患者的突变型葡糖脑苷脂酶。与对照葡萄糖脑苷脂酶一样，当在0.2M柠檬酸钠-磷酸盐缓冲液中进行β-葡萄糖苷酶测定时，1型葡萄糖脑苷脂酶对磷脂酰丝氨酸和硫苷脂无反应。基于这些脂质激活剂在两种缓冲液中的差异作用及其对突变酶的影响，我们提出，关于葡萄糖脑苷脂酶的脂质需求，有两类酸性脂质-一类由磷脂酰丝氨酸和硫苷脂组成，另一类由NGS、DHGS或牛磺脱氧胆酸钠等组成。似乎对照葡糖脑苷脂酶和1型戈谢病患者的突变酶可用第一类脂质重构，而2型患者的葡糖脑苷脂酶不可重构。本报告中的观察结果解释的模型，该模型假设正常的葡糖脑苷脂酶具有至少两个不同的脂质结合域。
The study of the acidic lipid requirement of human spleen glucocerebrosidase was extended to include two new series of acidic lipids, namely, monoacylglycol sulfates and diacylglycerol sulfates. Lysosomal glucocerebrosidase was extracted with sodium cholate and 1-butanol to render its β-glucosidase activity dependent upon exogenous lipids. Maximum reactivation of control glucocerebrosidase was obtained with nonanoylglycol sulfate (NGS) and diheptanoylglycerol sulfate (DHGS). However, the effects of these lipids were markedly dependent on the nature of buffer used in the assay medium; specifically, 0.2msodium citrate-phosphate (pH 5.5) was much more effective than 0.2msodium acetate (pH 5.5) in permitting these lipids to reactivate glucocerebrosidase. In contrast, the marked activation of glucocerebrosidase by phosphatidylserine and galactocerebroside 3-sulfate (sulfatide) that was achievable in the sodium acetate buffer was totally inhibited by citrate or phosphate ions. The effects of NGS and DHGS on the kinetic parameters of control glucocerebrosidase were to lower theKmfor the substrate, 4-methylumbelliferyl-β-d-glucoside from 5.5 mmto approximately 2 mm(in sodium citrate-phosphate buffer) and markedly increase theVmax. Furthermore, with DHGS, significant activation was achieved at concentrations below the lipid's critical micellar concentration. None of the monoacylglycol- or diacylglycerol sulfates were capable of stimulating mutant glucocerebrosidases from either type 1 (Ashkenazi-Jewish) or type 2 Gaucher's disease patients. Like control glucocerebrosidase, the type 1 glucocerebrosidase was unresponsive to phosphatidylserine and sulfatide when the β-glucosidase assay was conducted in 0.2msodium citrate-phosphate buffer. Based on the differential action of these lipid activators in the two buffers and their effects on the mutant enzymes, we propose that, with regard to the lipid requirement of glucocerebrosidase, there are two classes of acidic lipids—one comprised of phosphatidylserine and sulfatide and the other comprised of the likes of NGS, DHGS, or sodium taurodeoxycholate. It appears that control glucocerebrosidase and the mutant enzyme of the patient with type 1 Gaucher's disease is reconstitutable with the first class of lipids whereas the glucocerebrosidase of the type 2 patient is not. The observations in this report are interpreted in terms of a model which postulates that normal glucocerebrosidase possesses at least two distinct lipid binding domains.