Barthelson R, Widdicombe J
Cardiovascular Research Institute, University of California San Francisco 94143.
J Clin Invest. 1987 Dec;80(6):1799-802. doi: 10.1172/JCI113274.
Cl-impermeability in cystic fibrosis (CF) tracheal epithelium derives from a deficiency in the beta-adrenergic regulation of apical membrane Cl- channels. To test the possibility that cAMP-dependent kinase is the cause of this deficiency, we assayed this kinase in soluble fractions from cultured airway epithelial cells, including CF human tracheal epithelial cells. Varying levels of cAMP were used in these assays to derive both a Vmax and apparent dissociation constant (Kd) for the enzymes in soluble extracts. The cAMP-dependent protein kinase from CF human tracheal epithelial cells has essentially the same Vmax and apparent Kd as non-CF human, bovine, and dog tracheal epithelial cells. Thus, the total activity of the cAMP-dependent kinases and their overall responsiveness to cAMP are unchanged in CF.
囊性纤维化（CF）气管上皮细胞中的氯离子不通透性源于顶端膜氯离子通道的β-肾上腺素能调节缺陷。为了测试环磷酸腺苷（cAMP）依赖性激酶是否是导致这种缺陷的原因，我们对培养的气道上皮细胞（包括CF人气管上皮细胞）的可溶性组分中的这种激酶进行了测定。在这些测定中使用了不同水平的cAMP，以得出可溶性提取物中酶的最大反应速度（Vmax）和表观解离常数（Kd）。CF人气管上皮细胞中的cAMP依赖性蛋白激酶与非CF人、牛和犬气管上皮细胞中的Vmax和表观Kd基本相同。因此，CF中cAMP依赖性激酶的总活性及其对cAMP的总体反应性没有改变。
