Schneider P B, Kennedy E P
J Lipid Res. 1967 May;8(3):202-9.
This paper describes the purification and some of the properties of an enzyme from human spleen that catalyzes the hydrolysis of sphingomyelin with the formation of ceramide and phosphoryl choline. The enzyme, which is located in the subcellular particulate fraction that sediments between 700 and 8500 g, is readily made soluble and has been partially purified. Its pH optimum is between 4.5 and 5.0. It is unaffected by divalent cations, chelating agents, and sulfhydryl reagents, but is inhibited by phosphate. The enzyme attacks sphingomyelin and dihydrosphingomyelin, but is inactive toward sphingosine phosphoryl choline, O-acetylsphingomyelin, and lecithin. In some of its properties, the enzyme from human spleen is different from the previously studied sphingomyelinase from rat tissues. The enzyme is absent or markedly reduced in spleens from patients with classical and visceral varieties of Niemann-Pick disease, but is present in normal amounts in the late infantile type of the disease. In the present study another enzyme, this one magnesium-dependent, capable of catalyzing the cleavage of sphingomyelin has been detected in the spleens of patients with the classical form of Niemann-Pick disease. Some implications of these findings for theories of the metabolic defect in Niemann-Pick disease are discussed.
本文描述了一种从人脾脏中提取的酶的纯化过程及其一些特性，该酶催化鞘磷脂水解生成神经酰胺和磷酸胆碱。这种酶位于亚细胞颗粒组分中，在700至8500克离心力下沉淀，很容易溶解并已得到部分纯化。其最适pH值在4.5至5.0之间。它不受二价阳离子、螯合剂和巯基试剂的影响，但受磷酸盐抑制。该酶作用于鞘磷脂和二氢鞘磷脂，但对鞘氨醇磷酸胆碱、O - 乙酰鞘磷脂和卵磷脂无活性。在某些特性方面，人脾脏中的这种酶与先前研究的大鼠组织鞘磷脂酶不同。在经典型和内脏型尼曼 - 匹克病患者的脾脏中，这种酶缺失或明显减少，但在晚婴儿型疾病中含量正常。在本研究中，在经典型尼曼 - 匹克病患者的脾脏中检测到另一种酶，这种酶依赖镁，能够催化鞘磷脂的裂解。讨论了这些发现对尼曼 - 匹克病代谢缺陷理论的一些影响。
