PHOSPHOHEXOSYL RECOGNITION IS A GENERAL CHARACTERISTIC OF PINOCYTOSIS OF LYSOSOMAL GLYCOSIDASES BY HUMAN FIBROBLASTS
PHOSPHOHEXOSYL RECOGNITION IS A GENERAL CHARACTERISTIC OF PINOCYTOSIS OF LYSOSOMAL GLYCOSIDASES BY HUMAN FIBROBLASTS
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DOI：
10.1172/jci108860
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发表时间：
1977-01-01
影响因子：
15.9
通讯作者：
SLY, W
中科院分区：
文献类型：
--
作者：
KAPLAN, A;FISCHER, D;SLY, W
所提供的数据表明，6-磷酸甘露糖是人血小板β-葡萄糖醛酸酶胞饮作用的有效竞争性抑制剂，并且用碱性磷酸酶处理该酶的高摄取形式破坏了该酶的高摄取特性，而不降低其催化活性。这些数据表明，磷酸盐是人成纤维细胞胞饮作用酶上识别标记的必要组成部分，并表明该酶的高摄取形式上的磷酸盐以磷酸己糖基部分的形式存在。本文呈现的结果表明，6-磷酸甘露糖也是以下酶制剂胞饮作用的有效抑制剂：来自人脾、肝、胎盘和尿液的β-葡萄糖醛酸酶；来自人脾、肝、胎盘和尿液的β-葡萄糖醛酸酶；来自人血小板的β-氨基己糖苷酶和β-半乳糖苷酶；和来自人成纤维细胞分泌物的β-己糖胺酶。除β-半乳糖苷酶外，所有这些酶的碱性磷酸酶处理（β-半乳糖苷酶对温育条件不稳定且无法进行测试）大大降低了酶的摄取活性，但未降低其催化活性。这些结果表明磷酸己糖基识别是溶酶体糖苷酶胞饮作用的一般特征。
Data was presented showing that mannose-6-phosphate was a potent competitive inhibitor of pinocytosis of human platelet .beta.-glucuronidase, and that treatment of high-uptake forms of the enzyme with alkaline phosphatase destroyed the high-uptake property of the enzyme without diminishing its catalytic activity. These data indicated that phosphate was a necessary component of the recognition marker on the enzyme for pinocytosis by human fibroblasts, and suggested that the phosphate on high-uptake forms of the enzyme was present as a phosphohexosyl moiety. Results presented here showed that mannose-6-phosphate was also a potent inhibitor of pinocytosis of the following enzyme preparations: .beta.-glucuronidase from human spleen, liver, placenta and urine; .beta.-hexosaminidase and .beta.-galactosidase from human platelets; and .beta.-hexosaminidase from human fibroblast secretions. Alkaline phosphatase treatment of all of these enzymes except .beta.-galactosidase, which was unstable to the incubation conditions and could not be tested, greatly diminished the uptake activity of the enzymes without diminishing their catalytic activity. These results suggested that phosphohexosyl recognition was a general characteristic of pinocytosis of lysosomal glycosidases.