Goat liver beta-mannosidases: molecular properties, inhibition and inactivation of the lysosomal and nonlysosomal forms.
Goat liver beta-mannosidases: molecular properties, inhibition and inactivation of the lysosomal and nonlysosomal forms.
复制标题
山羊肝 β-甘露糖苷酶：溶酶体和非溶酶体形式的分子特性、抑制和失活。
DOI：
10.1159/000469366
复制
发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Wilkinson,FE
中科院分区：
文献类型：
--
作者：
Cavanagh,KT;Fisher,RA;Legler,G;Herrchen,M;Jones,MZ;Julich,E;Sewell-Alger,RP;Sinnott,ML;Wilkinson,FE
两种山羊肝 β-甘露糖苷酶已部分纯化，并对其特性进行了比较。溶酶体β-甘露糖苷酶A的表观分子量为127,000 ± 10,000，等电点为pH 6-7。其活性不受与 Triton X-100 (0.1 %) 和半胱氨酸 (20 mM) 一起孵育的影响，并且它会水解假定的天然底物 Man(ß1-4)GlcNAc 和 Man(ß1-4)GlcNaC(ß1-4)GlcNAc。非溶酶体β-甘露糖苷酶 B 的表观分子量为 43,000 ± 2,000，等电点为 pH 5.5。 ß-甘露糖苷酶 B 被 Triton X-100 (0.1 %) 激活，并被半胱氨酸 (20 mM) 抑制。与 ß-甘露糖苷酶 B 一起孵育后，Man(ß1-4)GlcNAc 会水解，但 Man(ß1-4)GlcNAc(ß1-4)GlcNAc 不会水解。1,5-二脱氧-1,5-亚氨基-D-甘露醇不会抑制 A 酶，仅微弱 (K(i) = 0.3 mM) 抑制 B 酶； ß-D-吡喃甘露糖基甲基对硝基苯基三氮烯不会使任一酶失活，但 1,2-anHydro-1,2,3,5,6/4-环己烷己醇仅使 B 酶失活。这两种酶之间的根本机制差异反对它们具有相同的遗传起源。
The two caprine hepatic ß-mannosidases have been partially purified and their properties have been compared. The lysosomal ß-mannosidase A had an apparent molecular weight of 127,000 ± 10,000 and an isoelectric point of pH 6-7. Its activity was unaffected by incubation with Triton X-100 (0.1 %) and cysteine (20 mM) and it hydrolyzed the presumed natural substrates, Man(ß1-4)GlcNAc and Man(ß1—4)GlcNaC(ß1-4)GlcNAc. The nonlysosomalß-mannosidase B had an apparent molecular weight of 43,000 ± 2,000 and an isoelectric point of pH 5.5. ß-Mannosidase B was activated by Triton X-100 (0.1 %) and was inhibited by cysteine (20 mM). Hydrolysis of Man(ß1-4)GlcNAc, but not of Man(ß1-4)GlcNAc(ß1-4)GlcNAc, followed incubation with ß-mannosidase B. 1,5-Dideoxy-1,5-imino-D-mannitol did not inhibit the A enzyme and only feebly (K(i) = 0.3 mM) inhibited the B enzyme; ß-D-mannopyranosylmethyl p-nitrophenyl triazene did not inactivate either enzyme but 1,2-anhydro-1,2,3,5,6/4-cyclohexane hexol inactivated the B enzyme only. The radical mechanistic differences between the two enzymes argue against their having the same genetic origin.