Physical properties of β‐N‐acetyl‐D‐glucosaminidase and β‐N‐acetyl‐D‐hexosaminidase from Drosophila Kc‐cells
Physical properties of β‐N‐acetyl‐D‐glucosaminidase and β‐N‐acetyl‐D‐hexosaminidase from Drosophila Kc‐cells
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果蝇 Kc 细胞的 β-N-乙酰基-D-氨基葡萄糖苷酶和 β-N-乙酰基-D-氨基己糖苷酶的物理性质
DOI：
10.1002/arch.940180105
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
K. Spindler
中科院分区：
文献类型：
--
作者：
U. Sommer;K. Spindler
果蝇的KC细胞产生两种不同的β-D-氨基己糖苷酶，一种是β-N-乙酰-D-氨基葡萄糖苷酶(E.C.3.2.1.30)，另一种是β-N-乙酰-D-氨基己糖苷酶(E.C.3.2.1.52)，这两种酶也分泌到培养液中。两种酶的相对分子质量约为126,000+/-9,700，S值为8.37+/-0.44。两种酶的最适pH值均为5.5，热稳定性也基本相同。如果以对硝基苯基-N-乙酰氨基葡萄糖为底物，两种酶的最适温度相同(50℃)。然而，当以对硝基苯基-N-乙酰半乳糖胺为底物时，β-N-乙酰基-D-氨基己糖苷酶的最适温度高出约10℃。随着盐浓度的增加，β-N-乙酰-D-氨基葡萄糖苷酶的活性增加，而β-N-乙酰-D-氨基己糖苷酶的活性受到抑制。这两种酶对尿素的敏感性也不同，β-N-乙酰-D-己糖苷酶的敏感性低于β-N-乙酰-D-氨基葡萄糖苷酶。
Kc-cells from Drosophila produce two different beta-D-hexosaminidases, a beta-N-acetyl-D-glucosaminidase (E.C.3.2.1.30) and a beta-N-acetyl-D-hexosaminidase (E.C.3.2.1.52), which are also secreted into the medium. The Mr of both enzymes is about 126,000 +/- 9,700; the S-values are 8.37 +/- 0.44. Both enzymes have about the same pH optima at 5.5 and the same thermal stability. The temperature optima are identical (50 degrees C) for both enzymes if p-nitrophenyl-N-acetylglucosaminide is used as a substrate. However, when p-nitrophenyl-N-acetylgalactosaminide is used as the substrate the beta-N-acetyl-D-hexosaminidase has a temperature optimum about 10 degrees C higher. With higher salt concentrations, the activity of the beta-N-acetyl-D-glucosaminidase increases, whereas beta-N-acetyl-D-hexosaminidase is inhibited. Both enzymes also differ in their sensitivity to urea, the beta-N-acetyl-D-hexosaminidase being less sensitive than the beta-N-acetyl-D-glucosaminidase.