火鸡红细胞上β-肾上腺素能受体的结合特性及数量
The binding characteristics and number of beta-adrenergic receptors on the turkey erythrocyte.
作者信息
Levitzki A, Atlas D, Steer M L
出版信息
Proc Natl Acad Sci U S A. 1974 Jul;71(7):2773-6. doi: 10.1073/pnas.71.7.2773.
Turkey erythrocyte ghosts (empty membranes) possess a class of receptors that can bind both L-[(3)H]isoproterenol and DL-[(3)H]propranolol. The binding of [(3)H]isoproterenol to these receptors occurs with a dissociation constant of 0.15 muM and can be fully inhibited by 1 muM propranolol. The binding of [(3)H]propranolol occurs with a dissociation constant of 2.5 nM and can be fully inhibited by 0.2 mM DL-isoproterenol. Ligand binding is sensitive to sonication, boiling, and 8 M urea. The cells possess 500 to 1000 beta-adrenergic receptors per cell. Binding of propranolol to the beta-receptor was found to be stereospecific for the L stereoisomer. If one assumed a 1:1 relationship between beta-adrenergic receptors and adenylate cyclase, the turnover number of this adenylate cyclase would be close to 100 min(-1).
土耳其红细胞血影（空膜）含有一类既能结合L-[(3)H]异丙肾上腺素又能结合DL-[(3)H]普萘洛尔的受体。[(3)H]异丙肾上腺素与这些受体的结合解离常数为0.15 μM，1 μM普萘洛尔可完全抑制其结合。[(3)H]普萘洛尔的结合解离常数为2.5 nM，0.2 mM DL-异丙肾上腺素可完全抑制其结合。配体结合对超声处理、煮沸和8 M尿素敏感。每个细胞拥有500至1000个β-肾上腺素能受体。发现普萘洛尔与β-受体的结合对L立体异构体具有立体特异性。如果假设β-肾上腺素能受体与腺苷酸环化酶之间为1:1关系，那么这种腺苷酸环化酶的转换数将接近100 min(-1)。
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