Elbein A D, Kerbacher J K, Schwartz C J, Sprague E A
Department of Biochemistry and Pathology, University of Texas Health Science Center, San Antonio 78284.
Arch Biochem Biophys. 1991 Jul;288(1):177-84. doi: 10.1016/0003-9861(91)90181-h.
Kifunensine is an alkaloid that is produced by the actinomycete Kitasatosporia kifunense and resembles the cyclic oxamide derivative of 1-aminodeoxymannojirimycin in structure. We previously showed that this compound was a potent inhibitor of the purified glycoprotein processing enzyme, mannosidase I, and caused an almost complete inhibition in the formation of complex types of oligosaccharides with the concurrent accumulation of N-linked oligosaccharides having Man9(GlcNAc)2 structures in influenza virus-infected Madin Darby canine kidney cells. Kifunensine, at concentrations of 1 microgram/ml or higher in the culture medium, caused an almost complete inhibition in the formation of complex types of oligosaccharides by human skin fibroblasts or aortic endothelial cells, with the resulting accumulation of Man9(GlcNAc)2 oligosaccharides on the cell surface N-linked glycoproteins, and more specifically on the scavenger-LDL receptor. When endothelial cells were grown in the presence of 1 microgram/ml of kifunensine, there was a 75% inhibition in the ability of these cells to degrade 125I-labeled acetyl-LDL, but this inhibitor appeared to have little or no effect on the ability of either endothelial cells or fibroblasts to degrade 125I-labeled LDL, even at kifunensine concentrations of 10 micrograms/ml. Kifunensine also decreased the binding of the labeled acetyl-LDL by the scavenger receptor of the endothelial cells, but the amount of this inhibition relative to controls was significantly less than that of the degradation, suggesting that kifunensine affects two different steps of acetyl-LDL metabolism in these cells. Endothelial cells grown in the presence of 10 micrograms/ml of kifunensine had only half the activity of the lysosomal enzymes, beta-hexosaminidase, and proteases, as did control cells, although kifunensine did not affect [3H]leucine incorporation into protein. Thus, kifunensine apparently affects the activity of (some) lysosomal enzymes in an as yet undefined manner.
kifunensine是一种由放线菌北里孢菌产生的生物碱，其结构类似于1-氨基脱氧甘露糖胺霉素的环状草酰胺衍生物。我们之前表明，该化合物是纯化的糖蛋白加工酶甘露糖苷酶I的有效抑制剂，在流感病毒感染的Madin Darby犬肾细胞中，它几乎完全抑制了复杂类型寡糖的形成，同时导致具有Man9(GlcNAc)2结构的N-连接寡糖的积累。在培养基中浓度为1微克/毫升或更高时，kifunensine几乎完全抑制了人皮肤成纤维细胞或主动脉内皮细胞中复杂类型寡糖的形成，导致Man9(GlcNAc)2寡糖在细胞表面N-连接糖蛋白上积累，更具体地说是在清道夫-LDL受体上积累。当内皮细胞在含有1微克/毫升kifunensine的条件下生长时，这些细胞降解125I标记的乙酰-LDL的能力受到75%的抑制，但即使在kifunensine浓度为10微克/毫升时，这种抑制剂似乎对内皮细胞或成纤维细胞降解125I标记的LDL的能力几乎没有影响。Kifunensine还降低了内皮细胞清道夫受体对标记的乙酰-LDL的结合，但相对于对照，这种抑制的量明显小于降解的抑制量，这表明kifunensine影响了这些细胞中乙酰-LDL代谢的两个不同步骤。在含有10微克/毫升kifunensine的条件下生长的内皮细胞，其溶酶体酶β-己糖胺酶和蛋白酶的活性只有对照细胞的一半，尽管kifunensine不影响[3H]亮氨酸掺入蛋白质。因此，kifunensine显然以一种尚未明确的方式影响（某些）溶酶体酶的活性。
