Grabowski G A, Gatt S, Horowitz M
Department of Pediatrics, Mount Sinai School of Medicine, New York, New York 10029.
Crit Rev Biochem Mol Biol. 1990;25(6):385-414. doi: 10.3109/10409239009090616.
Human lysosomal beta-glucosidase (D-glucosyl-acylsphingosine glucohydrolase, EC 3.2.1.45) is a membrane-associated enzyme that cleaves the beta-glucosidic linkage of glucosylceramide (glucocerebroside), its natural substrate, as well as synthetic beta-glucosides. Experiments with cultured cells suggest that in vivo this glycoprotein requires interaction with negatively charged lipids and a small acidic protein, SAP-2, for optimal glucosylceramide hydrolytic rates. In vitro, detergents (Triton X-100 or bile acids) or negatively charged ganglioside or phospholipids and one of several "activator proteins" increase hydrolytic rate of lipid and water-soluble substrates. Using such in vitro assay systems and active site-directed covalent inhibitors, kinetic and structural properties of the active site have been elucidated. The defective activity of this enzyme leads to the variants of Gaucher disease, the most prevalent lysosomal storage disease. The nonneuronopathic (type 1) and neuronopathic (types 2 and 3) variants of this inherited (autosomal recessive) disease but panethnic, but type 1 is most prevalent in the Ashkenazi Jewish population. Several missense mutations, identified in the structural gene for lysosomal beta-glucosidase from Gaucher disease patients, are presumably casual to the specifically altered posttranslational oligosaccharide processing or stability of the enzyme as well as the altered in vitro kinetic properties of the residual enzyme from patient tissues.
人溶酶体β-葡萄糖苷酶（D-葡萄糖基-酰基鞘氨醇葡萄糖水解酶，EC 3.2.1.45）是一种与膜相关的酶，可切割其天然底物葡萄糖神经酰胺（葡糖脑苷脂）以及合成β-葡萄糖苷的β-糖苷键。对培养细胞进行的实验表明，在体内，这种糖蛋白需要与带负电荷的脂质和一种小的酸性蛋白SAP-2相互作用，以实现最佳的葡萄糖神经酰胺水解速率。在体外，洗涤剂（Triton X-100或胆汁酸）或带负电荷的神经节苷脂或磷脂以及几种“激活蛋白”之一可提高脂质和水溶性底物的水解速率。使用此类体外测定系统和活性位点导向的共价抑制剂，已阐明了活性位点的动力学和结构特性。这种酶的活性缺陷会导致戈谢病的各种变体，戈谢病是最常见的溶酶体贮积病。这种遗传性（常染色体隐性）疾病的非神经病变型（1型）和神经病变型（2型和3型）在各民族中均有发生，但1型在德系犹太人群中最为常见。在戈谢病患者的溶酶体β-葡萄糖苷酶结构基因中鉴定出的几种错义突变，可能是导致翻译后寡糖加工或酶稳定性发生特异性改变以及患者组织中残留酶的体外动力学特性改变的原因。
