Christomanou H, Kleinschmidt T
Biol Chem Hoppe Seyler. 1985 Mar;366(3):245-56. doi: 10.1515/bchm3.1985.366.1.245.
Two activator proteins for sphingomyelin degradation were isolated from heat-treated extracts of human Gaucher spleen. The separation was based on the degree of affinity of the activators for ConA-Sepharose. Activator A1, which had affinity for ConA-Sepharose, was purified 1 430-fold, and activator A2, which had no affinity for ConA-Sepharose, 2 140-fold as compared with the original heat-treated extracts. The molecular masses of activator A1 and activator A2 were 6 000 and 3 500 Da, respectively, as determined by dodecyl sulfate electrophoresis, and approximately 5 000 Da as measured in the presence of 8M urea. The two activators had similar properties and a similar but not identical amino-acid composition. Both were shown to form a complex with sphingomyelin and stimulate the degradation of sphingomyelin by normal fibroblast homogenates and by an approximately 1 430-fold purified sphingomyelin phosphodiesterase ("acid sphingomyelinase") from normal human urine. This stimulation was greatly reduced after incubation with pronase E. The enzymic degradation of glucosylceramide and galactosylceramide was not affected by these activators.
从经热处理的戈谢病患者脾脏提取物中分离出两种鞘磷脂降解激活蛋白。分离基于激活蛋白与刀豆球蛋白A-琼脂糖的亲和程度。与原始经热处理的提取物相比，对刀豆球蛋白A-琼脂糖有亲和力的激活蛋白A1纯化了1430倍，对刀豆球蛋白A-琼脂糖无亲和力的激活蛋白A2纯化了2140倍。通过十二烷基硫酸钠电泳测定，激活蛋白A1和激活蛋白A2的分子量分别为6000和3500道尔顿，在8M尿素存在下测量约为5000道尔顿。这两种激活蛋白具有相似的性质和相似但不完全相同的氨基酸组成。二者均显示与鞘磷脂形成复合物，并刺激正常成纤维细胞匀浆以及来自正常人尿液的经约1430倍纯化的鞘磷脂磷酸二酯酶（“酸性鞘磷脂酶”）对鞘磷脂的降解。与链霉蛋白酶E孵育后，这种刺激作用大大降低。这些激活蛋白对葡糖神经酰胺和半乳糖神经酰胺的酶促降解没有影响。
