6-磷酸己糖脱氢酶作为氧化还原酶决定11β-羟基类固醇脱氢酶1型的反应方向。
Hexose-6-phosphate dehydrogenase determines the reaction direction of 11beta-hydroxysteroid dehydrogenase type 1 as an oxoreductase.
作者信息
Atanasov Atanas G, Nashev Lyubomir G, Schweizer Roberto A S, Frick Christoph, Odermatt Alex
机构信息
Division of Nephrology and Hypertension, Department of Clinical Research, University of Berne, Freiburgstrasse 15, 3010 Berne, Switzerland.
出版信息
FEBS Lett. 2004 Jul 30;571(1-3):129-33. doi: 10.1016/j.febslet.2004.06.065.
The impact of hexose-6-phosphate dehydrogenase (H6PDH) on 11beta-hydroxysteroid dehydrogenase (11beta-HSD) type 1 activity was investigated upon coexpression in HEK-293 cells. Confocal microscopy analysis indicated colocalisation of both enzymes at the lumenal side of the endoplasmic reticulum (ER) membrane. Functional analysis in intact cells revealed fivefold stimulation of 11beta-HSD1 oxoreductase activity and sixfold decrease of dehydrogenase activity upon coexpression with H6PDH, without changing kinetic parameters in cell lysates. Thus, H6PDH directly determines the reaction direction of 11beta-HSD1 in intact cells as an oxoreductase without changing intrinsic catalytic properties of 11beta-HSD1 by regenerating NADPH in the ER-lumen.
在HEK-293细胞中共表达时，研究了己糖-6-磷酸脱氢酶（H6PDH）对1型11β-羟基类固醇脱氢酶（11β-HSD）活性的影响。共聚焦显微镜分析表明，两种酶在内质网（ER）膜的腔侧共定位。完整细胞中的功能分析显示，与H6PDH共表达时，11β-HSD1氧化还原酶活性提高了五倍，脱氢酶活性降低了六倍，而细胞裂解物中的动力学参数没有变化。因此，H6PDH通过在内质网腔中再生NADPH，直接决定了完整细胞中11β-HSD1作为氧化还原酶的反应方向，而不改变11β-HSD1的内在催化特性。
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