Saito M, Yu R K
Department of Biochemistry and Molecular Biophysics, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298.
J Neurochem. 1992 Jan;58(1):83-7. doi: 10.1111/j.1471-4159.1992.tb09280.x.
The role of myelin-associated neuraminidase in ganglioside metabolism was examined using rats of ages ranging from 17 to 97 days. The neuraminidase activity directed toward the ganglioside GM3 in the total myelin fraction was high during the period of active myelination and, thereafter, decreased rapidly to the adult level. The ganglioside composition became simpler during development with an increasing amount of GM1 and decreasing percentages of di- and polysialogangliosides. The decrease in the proportion of GD1a was most prominent, whereas relative amounts of GD1b and GT1b increased transiently before reducing to the adult levels. The heavy myelin subfraction contained higher percentages of di- and polysialo-species compared to the light myelin fraction at young and adult ages. The in vitro incubation of myelin of young rats under an optimal condition for neuraminidase action produced a profile of ganglioside changes similar to that observed in in vivo development. These results strongly suggest that myelin-associated neuraminidase may play a pivotal role in the developmental changes in the ganglioside composition of rat brain myelin.
利用17至97日龄的大鼠，研究了髓鞘相关神经氨酸酶在神经节苷脂代谢中的作用。在活跃髓鞘形成期，总髓鞘部分中针对神经节苷脂GM3的神经氨酸酶活性较高，此后迅速降至成年水平。在发育过程中，神经节苷脂组成变得更简单，GM1含量增加，二唾液酸和多唾液酸神经节苷脂的百分比降低。GD1a比例的下降最为显著，而GD1b和GT1b的相对含量在降至成年水平之前短暂增加。在幼年和成年期，重髓鞘亚组分中双唾液酸和多唾液酸种类的百分比高于轻髓鞘组分。在神经氨酸酶作用的最佳条件下，对幼鼠髓鞘进行体外孵育，产生的神经节苷脂变化谱与体内发育过程中观察到的相似。这些结果有力地表明，髓鞘相关神经氨酸酶可能在大鼠脑髓鞘神经节苷脂组成的发育变化中起关键作用。
