Li S C, Nakamura T, Ogamo A, Li Y T
J Biol Chem. 1979 Nov 10;254(21):10592-5.
Two different protein activators were isolated simultaneously from human liver for the enzymic hydrolysis of GM1 (Gal beta 1 leads to 3GalNAc beta 1 leads to 4Gal(3 comes from 2 alpha NeuAc)beta 1 leads to 4Glc-Cer) by beta-galactosidase and GM2 (GalNAc beta 1 leads to 4Gal(3 comes from 2 alpha NeuAc)beta 1 leads to 4Glc-Cer) by beta-hexosaminidase A. The hydrolysis of GM1 is stimulated only by the GM1-specific activator which has very little effect on the hydrolysis of GM2. The same is also true for the hydrolysis of GM2. The antiserum raised against GM1 activator did not cross-react with GM2 activator and vice versa. These results suggest the presence of two different activators for the separate hydrolysis of GM1 and GM2. In connection with the enzymic hydrolysis of GM1 and GM2, we found that the hydrolysis of GM2 by human hepatic beta-N-acetylhexosaminidase A was severely inhibited by a buffer of high ionic strength, whereas no such inhibition was observed in the hydrolysis of GM1 by beta-galactosidase.
从人肝脏中同时分离出两种不同的蛋白质激活剂，一种用于β-半乳糖苷酶对GM1（Galβ1→3GalNAcβ1→4Gal（3位来自2α-NeuAc）β1→4Glc-Cer）的酶促水解，另一种用于β-N-乙酰己糖胺酶A对GM2（GalNAcβ1→4Gal（3位来自2α-NeuAc）β1→4Glc-Cer）的酶促水解。GM1的水解仅受GM1特异性激活剂的刺激，该激活剂对GM2的水解几乎没有影响。GM2的水解情况也是如此。针对GM1激活剂产生的抗血清与GM2激活剂不发生交叉反应，反之亦然。这些结果表明存在两种不同的激活剂，分别用于GM1和GM2的水解。关于GM1和GM2的酶促水解，我们发现人肝脏β-N-乙酰己糖胺酶A对GM2的水解受到高离子强度缓冲液的严重抑制，而β-半乳糖苷酶对GM1的水解未观察到这种抑制作用。
