Yoshimura M, Ihara Y, Taniguchi N
Department of Biochemistry, Osaka University Medical School, Japan.
Glycoconj J. 1995 Jun;12(3):234-40. doi: 10.1007/BF00731325.
Changes in the activity and transcription of UDP-N-acetylglucosamine: beta-D-mannoside beta-1,4-N-acetylglucosaminyl-transferase III (GnT-III: EC 2.4.1.144) were investigated in haematological malignancies. GnT-III activity was elevated in patients with chronic myelogeneous leukaemia in blast crisis (CML-BC) and patients with multiple myeloma (MM); whereas most of the normal healthy subjects and patients with other haematological malignancies, including CML in its chronic phase, showed negligible activity. The GnT-III transcript of leukaemic cells from various haematological diseases showed a single band with a similar size. The ratio of GnT-III activity per normalized transcript in CML-BC was considerably higher than in the other conditions, which provided the possibility that in CML-BC the transcript or the enzyme protein might be more stable, or that a post-translational modification of the enzyme might enhance its activity. Furthermore, a lectin blot analysis of patient specimens and a lectin fluorescence study of CML cell lines revealed that E4-PHA binding to surface glycoproteins correlated with GnT-III activity, indicating that more bisecting GlcNAc was added to these glycoproteins, catalysed by elevated GnT-III in CML-BC.
在血液系统恶性肿瘤中研究了UDP-N-乙酰葡糖胺：β-D-甘露糖苷β-1,4-N-乙酰葡糖胺基转移酶III（GnT-III：EC 2.4.1.144）的活性和转录变化。在急变期慢性粒细胞白血病（CML-BC）患者和多发性骨髓瘤（MM）患者中，GnT-III活性升高；而大多数正常健康受试者和其他血液系统恶性肿瘤患者，包括慢性期CML患者，其活性可忽略不计。来自各种血液系统疾病的白血病细胞的GnT-III转录本显示出一条大小相似的单带。CML-BC中每标准化转录本的GnT-III活性比率明显高于其他情况，这表明在CML-BC中，转录本或酶蛋白可能更稳定，或者酶的翻译后修饰可能增强其活性。此外，对患者标本的凝集素印迹分析和对CML细胞系的凝集素荧光研究表明，E4-PHA与表面糖蛋白的结合与GnT-III活性相关，表明在CML-BC中升高的GnT-III催化更多的平分型GlcNAc添加到这些糖蛋白上。
