Physicochemical characterization of a ouabain isomer isolated from bovine hypothalamus.
Physicochemical characterization of a ouabain isomer isolated from bovine hypothalamus.
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从牛下丘脑分离的哇巴因异构体的物理化学特征。
DOI：
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发表时间：
1993
影响因子：
11.1
通讯作者：
G. T. Haupert
中科院分区：
文献类型：
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作者：
A. Tymiak;Jon A. Norman;M. Bolgar;G. Didonato;Helen Lee;William L. Parker;LEE;Lot;Nina;BEROVAt;KoJI;NAKANISHIt;Edgar Haber;G. T. Haupert
最近的报告显示，在人类中存在一种哇巴因样Na+/K（+）-ATP酶抑制剂。用亲和层析结合高效液相色谱法纯化了牛下丘脑Na+/K（+）-ATP酶抑制因子（HIF）。该抑制剂的分子量为584，通过离子喷雾质谱法测定，使其与哇巴因等重。糖苷酶处理或酸水解的HIF释放只有L-鼠李糖，己糖异构体中发现哇巴因，通过手性GC/MS检测。此外，酶促产生的去鼠李糖HIF被发现具有438的分子量，哇巴苷元，哇巴因的糖苷配基。HIF和它的苷元是无法区分的哇巴因和哇巴皂苷元，分别通过反相HPLC保留时间。然而，用萘酰咪唑衍生化，然后用HPLC显示HIF和哇巴因的萘酰化产物的保留时间不同。随后对HIF和哇巴因的分离的萘甲酰化产物的CD光谱证实它们是不同的。本研究提供了色谱和光谱证据，哇巴因和HIF是异构体的强心内酯。结构差异被假定为解释HIF和哇巴因观察到的生物学特性的显著差异。
Recent reports have shown the presence of a ouabain-like inhibitor of Na+/K(+)-ATPase in humans. We have purified a bovine hypothalamic Na+/K(+)-ATPase inhibitory factor (HIF) by using affinity chromatography combined with HPLC. This inhibitor has a molecular weight of 584 as determined by ion-spray mass spectrometry, making it isobaric with ouabain. Glycosidase treatment or acid hydrolysis of HIF released only L-rhamnose, the hexose isomer found in ouabain, as detected by chiral GC/MS. Additionally, enzymatically generated desrhamnosyl HIF was found to have a molecular weight of 438, as does ouabagenin, the aglycone of ouabain. HIF and its aglycone were indistinguishable from ouabain and ouabagenin, respectively, by reversed-phase HPLC retention times. However, derivatization with naphthoylimidazole followed by HPLC revealed different retention times for naphthoylation products of HIF and ouabain. Subsequent CD spectroscopy on isolated naphthoylation products of HIF and ouabain confirmed that they were different. This study provides chromatographic and spectroscopic evidence that ouabain and HIF are isomeric cardenolides. The structural difference is presumed to account for the significant differences in biological properties observed for HIF and ouabain.