Potier M, Beauregard G, Bélisle M, Mameli L, Hong V N, Melançon S B, Dallaire L
Clin Chim Acta. 1979 Dec 3;99(2):97-105. doi: 10.1016/0009-8981(79)90031-7.
Two neuraminidase (EC 3.2.1.18) comonents, A and B, were distinguished in cultured skin fibroblasts on the basis of thermolability at 37 degrees C. The more labile component (A) t1/2 = 4.7--5.3 min at 37 degrees C, comprises 66--90% of total neuraminidase activity when determined using sodium (4-methylumbelliferyl-alpha-D-N-acetylneuraminate) (MU-alpha-N) as substrate. Activity was assayed at 0 degrees C for 18 h instead of 37 degrees C to fully determine both thermolabile and thermostable components. Diminished activity was noted in cultured fibroblasts from mucolipidoses I, II and III (MLI, MLII, MLIII) and the cherry-red spot myoclonus syndrome (CRSM) patients when assayed at both 0 and 37 degrees C with either MU-alpha-N or each of a series alpha (2 leads to 3)- and alpha (2 leads to 6)-linked N-acetylneuraminyloligosaccharides. Increased sensitivity and rapidity of analyses were achieved using MJ-alpha-N as substrate in determining neuraminidase activity. Results from two obligate heterozygote MLI cell lines (14.5 and 8.0% of control activity) indicate that the MU-alpha-N substrate could be useful for heterozygote detection.
基于在37℃下的热稳定性，在培养的皮肤成纤维细胞中区分出两种神经氨酸酶（EC 3.2.1.18）成分，A和B。更不稳定的成分（A）在37℃下的半衰期t1/2 = 4.7 - 5.3分钟，当使用钠（4-甲基伞形酮基-α-D-N-乙酰神经氨酸）（MU-α-N）作为底物测定时，占总神经氨酸酶活性的66 - 90%。为了充分测定热不稳定和热稳定成分，在0℃下测定活性18小时而不是在37℃下。当用MU-α-N或一系列α（2→3）-和α（2→6）-连接的N-乙酰神经氨酰寡糖中的每一种在0℃和37℃下测定时，在黏脂贮积症I、II和III（MLI、MLII、MLIII）以及樱桃红斑肌阵挛综合征（CRSM）患者的培养成纤维细胞中观察到活性降低。在测定神经氨酸酶活性时，使用MJ-α-N作为底物可提高分析的灵敏度和速度。来自两个 obligate杂合子MLI细胞系的结果（对照活性的14.5%和8.0%）表明，MU-α-N底物可用于杂合子检测。
