Chiral synthesis of a dithiolester analog of phosphatidylcholine as a substrate for the assay of phospholipase A2.
Chiral synthesis of a dithiolester analog of phosphatidylcholine as a substrate for the assay of phospholipase A2.
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磷脂酰胆碱二硫醇酯类似物的手性合成作为磷脂酶 A2 测定的底物。
DOI：
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发表时间：
1983
影响因子：
6.5
通讯作者：
R. H. Dybvig
中科院分区：
文献类型：
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作者：
H. Hendrickson;E. K. Hendrickson;R. H. Dybvig
报道了磷脂酰胆碱的二硫酯类似物1，2-bis(heptanoylthio)-1，2-dideoxy-sn-glycerol-3-phosphocholine(硫代PC)的合成。以D-甘露醇制备的1-三叔丁基-n-甘油为起始原料，对甲苯磺化，然后用甲基黄原酸钾置换，得到三硫代碳酸酯。后者的还原裂解得到1，2-二硫醇，然后与磷酸胆碱进行酰化、去硝化和酯化。用磷脂酶A2(Naja NAJA)对硫代PC进行水解，手性纯度为95%。水解率随底物浓度的变化在0.17 mM处急剧增加，0.17 mM是脂质的临界胶束浓度。用分光光度法测定磷脂酶A2(在二硫代硝基苯甲酸存在下测定释放的硫醇基团)是相当灵敏的。只检测到1 ng的酶，相当于每分钟大约0.2nmol底物的水解率。
The synthesis of a dithiolester analog of phosphatidylcholine, 1,2-bis(heptanoylthio)-1,2-dideoxy-sn-glycerol-3-phosphocholine (thio PC), is described. Starting with 1-trityl-sn-glycerol (prepared from D-mannitol), tosylation followed by displacement with potassium methyl xanthate gave a trithiocarbonate. Reductive cleavage of the latter gave a 1,2-dithiol which was then acylated, detritylated, and esterified with choline phosphate. Hydrolysis of thio PC by phospholipase A2 (Naja naja) indicated 95% chiral purity. The rate of hydrolysis as a function of substrate concentration showed a sharp increase at about 0.17 mM, the critical micellar concentration of the lipid. A spectrophotometric assay of phospholipase A2 (by measurement of released thiol groups in the presence of dithionitrobenzoic acid) was quite sensitive. As little as 1 ng of enzyme was detected, representing a rate of about 0.2 nmol of substrate hydrolyzed per min.