Ohta H, Sawabu N, Odani H, Kawakami H, Watanabe H, Toya D, Ozaki K, Hattori N
Department of Internal Medicine, School of Medicine, Kanazawa University, Japan.
Pancreas. 1990;5(1):82-90. doi: 10.1097/00006676-199001000-00012.
To elucidate the specific changes of pancreatic gamma-glutamyl-transpeptidase (gamma-GTP) associated with malignant transformation, some properties of gamma-GTP purified from pancreatic cancer were compared with those of gamma-GTPs from normal pancreas and other tissues. Four of five pancreatic cancer gamma-GTPs showed distinctly slower electrophoretic mobility than normal pancreatic enzymes. Isoelectric points of pancreatic cancer gamma-GTPs varied in each case, but they were all higher than those of normal pancreatic enzymes. This difference in isoelectric points of gamma-GTPs between cancerous tissue and normal tissue was reduced by neuraminidase treatment. Lectin affinity chromatography revealed two of five pancreatic cancer gamma-GTPs with a greater affinity to concanavalin A (Con A) than normal pancreas gamma-GTPs. Four of five pancreatic cancer gamma-GTPs had a greater affinity to Lens culinaris agglutinin (LCA) than normal pancreas gamma-GTPs. Normal pancreas gamma-GTPs had little affinity to Phaseolus vulgaris erythroagglutinating (E-PHA), but two of five pancreatic cancer gamma-GTPs had an apparent affinity to E-PHA and one of them had a slight affinity to E-PHA. These results indicate that the transformational changes of pancreatic cancer gamma-GTP are mainly induced in the sugar chains of the enzyme molecule, resulting in lower content of sialic acid and higher content of fucose and bisecting GlcNAc residue (the beta-N-acetylglucosamine residue linked at the C-4 of the beta-mannosyl residue of the trimannosyl core of the asparagine-linked sugar chain) as compared with the normal pancreatic enzyme.
为阐明与恶性转化相关的胰腺γ-谷氨酰转肽酶（γ-GTP）的具体变化，将从胰腺癌中纯化的γ-GTP的一些特性与正常胰腺和其他组织中的γ-GTP特性进行了比较。5个胰腺癌γ-GTP中有4个的电泳迁移率明显低于正常胰腺酶。胰腺癌γ-GTP的等电点在每种情况下各不相同，但均高于正常胰腺酶的等电点。经神经氨酸酶处理后，癌组织和正常组织中γ-GTP等电点的这种差异减小。凝集素亲和层析显示，5个胰腺癌γ-GTP中有2个对伴刀豆球蛋白A（Con A）的亲和力高于正常胰腺γ-GTP。5个胰腺癌γ-GTP中有4个对扁豆凝集素（LCA）的亲和力高于正常胰腺γ-GTP。正常胰腺γ-GTP对菜豆红细胞凝集素（E-PHA）几乎没有亲和力，但5个胰腺癌γ-GTP中有2个对E-PHA有明显亲和力，其中1个对E-PHA有轻微亲和力。这些结果表明，胰腺癌γ-GTP的转化变化主要在酶分子的糖链中诱导产生，与正常胰腺酶相比，导致唾液酸含量降低，岩藻糖和平分型N-乙酰葡糖胺残基（与天冬酰胺连接糖链三甘露糖核心的β-甘露糖基残基的C-4位相连的β-N-乙酰葡糖胺残基）含量升高。
