Mechanism of action of choleragen and the glycopeptide hormones: is the nicotinamide adenine dinucleotide glycohydrolase activity observed in purified hormone preparations intrinsic to the hormone?
Mechanism of action of choleragen and the glycopeptide hormones: is the nicotinamide adenine dinucleotide glycohydrolase activity observed in purified hormone preparations intrinsic to the hormone?
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胆原和糖肽激素的作用机制：在纯化的激素制剂中观察到的烟酰胺腺嘌呤二核苷酸糖水解酶活性是否是激素固有的？
作者：
J. Moss;P. S. Ross;G. Agosto;S. Birken;R. Canfield;M. Vaughan
霍乱原和糖肽激素被认为是通过激活腺苷环化酶对细胞发挥作用的。霍乱原的催化亚基具有NAD糖水解酶和ADP-核糖基转移酶活性。由于糖肽激素与霍乱原具有某些结构上的同源性(Ledley等人，Biochem。生物群落。[中英文摘要]Re.Commun.69：852,1976)，我们研究了这些激素是否可能催化NAD糖水解酶反应。霍乱原激活牛甲状腺颗粒腺苷环化酶需要NAD，而牛TSH则不需要。高纯度的人CG(HCG)和牛TSH制剂具有NAD糖水解酶活性。这种活性存在于人绒毛膜促性腺激素的α和β亚基的明显均一的制剂中，也存在于去乙酰化或还原的羧甲基化衍生物中。然而，重组hCG亚单位，恢复了生物学效力，并没有产生NAD糖水解酶活性的增强。此外，这项活动也没有起到协同作用。
Choleragen and the glycopeptide hormones are thought to exert their effects on cells through activation of adenylate cyclase. The catalytic subunit of choleragen possesses both NAD glycohydrolase and ADP-ribosyltransferase activities. Since the glycopeptide hormones share with choleragen certain homologies of structure (Ledley et al, Biochem. Biophys. Res. Commun. 69: 852, 1976), we investigated whether these hormones might catalyze a NAD glycohydrolase reaction. NAD was required for activation of bovine thyroid particulate adenylate cyclase by choleragen, but not by bovine TSH. Highly purified preparations of human CG (hCG) and bovine TSH possessed NAD glycohydrolase activity. This activity was present in apparently homogeneous preparations of the α and β subunits of hCG and in the asialo or reduced carboxymethylated derivatives. Recombination of the hCG subunits, which restores biological potency, did not, however, produce enhancement of NAD glycohydrolase activity. Furthermore, this activity did not co...