锌对大鼠小肠刷状缘碳酸氢根刺激的ATP酶活性表现的需求。
Requirement of Zn to demonstrate HCO3-stimulated ATPase activity of rat small intestinal brush border.
作者信息
Kaysen G A, Chou L Y, Humphreys M H
出版信息
J Cell Biol. 1979 Sep;82(3):780-2. doi: 10.1083/jcb.82.3.780.
The existence of a membrane-bound HCO3-stimulated ATPase in intestinal mucosa is controversial. A crude brush border fraction of rat small intestinal homogenates contained HCO3-ATPase activity which was inhibited by preincubation with 3 mM EDTA. Alkaline phosphatase activity of this preparation was also inhibited in a parallel, time-dependent fashion by preincubation with EDTA. When 5 mM ZnSO4 accompanied 3 mM EDTA in the preincubation mix, preservation of both enzyme activities occurred, demonstrating a requirement of Zn for the activity of both these phosphatases. These studies support the earlier contention that HCO3-ATPase and alkaline phosphatase activities may be different properties of the same enzyme, and raise the possibility that the ATPase could play a role in intestinal ion transport. The failure to identify a membrane-bound HCO3-ATPase by other workers could be due to the exposure of EDTA which occurred in their tissue preparation.
肠黏膜中是否存在膜结合的HCO₃刺激的ATP酶仍存在争议。大鼠小肠匀浆的粗刷状缘部分含有HCO₃ - ATP酶活性，用3 mM EDTA预孵育可抑制该活性。该制剂的碱性磷酸酶活性也以平行的、时间依赖性方式被EDTA预孵育所抑制。当在预孵育混合物中5 mM ZnSO₄与3 mM EDTA同时存在时，两种酶活性均得以保留，表明这两种磷酸酶的活性均需要锌。这些研究支持了早期的观点，即HCO₃ - ATP酶和碱性磷酸酶活性可能是同一种酶的不同特性，并增加了ATP酶可能在肠道离子转运中起作用的可能性。其他研究人员未能鉴定出膜结合的HCO₃ - ATP酶，可能是由于他们在组织制备过程中暴露于EDTA。
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