Bruzik K, Jiang R T, Tsai M D
Biochemistry. 1983 May 10;22(10):2478-86. doi: 10.1021/bi00279a026.
The thiophospholipid 1,2-dipalmitoyl-sn-glycero-3-thiophosphocholine (DPPsC) was shown to be a mixture of two diastereomers by 31P nuclear magnetic resonance. The isomer that resonates at the lower field in CDCl3 (56.12 ppm) was designated as isomer A and the other (resonates at 56.07 ppm) as isomer B. Phospholipase A2 from four different sources (bee venom, Naja naja venom, Crotalus adamanteus venom, and porcine pancreas) was shown to hydrolyze the isomer B of DPPsC specifically, whereas phospholipase C from two different sources (Bacillus cereus and Clostridium perfringens) hydrolyzes isomer A specifically. So that the two diastereomers could be separated, DPPsC(A + B) was first digested with phospholipase A2 to give 1-palmitoyl-sn-glycero-3-thiophosphocholine (MPPsC) (which is designated as isomer B of MPPsC) and the unreacted DPPsC(A). Reacylation of MPPsC(B) gave pure DPPsC(B). The properties of DPPsC(A) and DPPsC(B) were investigated by 31P, 13C, 1H, and 14N nuclear magnetic resonance (NMR). 1H and 13C NMR showed that both isomers in methanol solution have conformational properties similar to those of the natural phospholipid, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine. On the other hand, the two isomers A and B showed small but significant differences in the chemical shifts of the carbon in the chiral carbon center and the phosphorus in the chiral phosphorus center.
通过³¹P核磁共振表明，硫代磷脂1,2 - 二棕榈酰 - sn - 甘油 - 3 - 硫代磷酸胆碱（DPPsC）是两种非对映异构体的混合物。在CDCl₃中低场共振的异构体（56.12 ppm）被指定为异构体A，另一种（在56.07 ppm共振）为异构体B。来自四种不同来源（蜂毒、眼镜蛇毒、金刚背响尾蛇毒和猪胰腺）的磷脂酶A₂被证明能特异性水解DPPsC的异构体B，而来自两种不同来源（蜡状芽孢杆菌和产气荚膜梭菌）的磷脂酶C能特异性水解异构体A。为了分离这两种非对映异构体，首先用磷脂酶A₂消化DPPsC（A + B），得到1 - 棕榈酰 - sn - 甘油 - 3 - 硫代磷酸胆碱（MPPsC）（被指定为MPPsC的异构体B）和未反应的DPPsC（A）。MPPsC（B）的再酰化得到纯的DPPsC（B）。通过³¹P、¹³C、¹H和¹⁴N核磁共振（NMR）研究了DPPsC（A）和DPPsC（B）的性质。¹H和¹³C NMR表明，在甲醇溶液中，两种异构体都具有与天然磷脂1,2 - 二棕榈酰 - sn - 甘油 - 3 - 磷酸胆碱相似的构象性质。另一方面，异构体A和B在手性碳中心的碳和手性磷中心的磷的化学位移上显示出微小但显著的差异。
