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作者观察了小鼠肝脏芳香酰胺酶分子中唾液酸残基对酶稳定性及催化性质的影响,发现酶的唾液酸残基去除后,对尿素失活率不变,对热稳定性可见降低;但是Co~(2+)激活程度、氨基酸(Phe、Met、Leu)抑制程度与抑制常数以及对底物L-亮氨酰β-萘胺的Km值等都保持不变,说明糖链末端唾液酸尽管携带负电荷但并不妨碍底物、Go~(2+)和氨基酸等与酶分子相应部位的结合,因此可推测唾液酸至少不影响活性部位局部的立体结构。
The authors observed the mouse hepatic aromatic amidase molecule sialic acid residues on the enzyme stability and catalytic properties and found that the enzyme sialic acid residues removed, the same rate of urea inactivation, the thermal stability can be seen reduced; However, the degree of activation of Co 2+, the degree of inhibition of the amino acids (Phe, Met, Leu) and the inhibition constant and the Km value of the substrate L-leucylβ-naphthylamine remained unchanged, indicating that the salivary Although the acid carries a negative charge without interfering with the binding of the substrate, Go2 and amino acids to the corresponding part of the enzyme molecule, it is presumed that the sialic acid does not affect at least the local stereostructure of the active site.