Alterations of membrane glycopeptides in human colonic adenocarcinoma.
Alterations of membrane glycopeptides in human colonic adenocarcinoma.
复制标题
人结肠腺癌中膜糖肽的改变。
DOI：
10.1073/pnas.71.12.4869
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发表时间：
1974
影响因子：
11.1
通讯作者：
J. Perdomo
中科院分区：
文献类型：
--
作者：
Y. S. Kim;R. Isaacs;J. Perdomo
本文对人结肠腺癌和正常结肠粘膜的膜糖肽进行了检测。发现肿瘤组织中膜糖肽的碳水化合物显著减少，各种糖的相对比例发生改变。虽然所有的糖在肿瘤组织中较低时，与邻近的正常粘膜，半乳糖胺，岩藻糖，唾液酸更显着减少。血型活性和膜糖肽的凝集素结合特性的检查显示，特定的碳水化合物结构在肿瘤组织中发生了变化。这些变化中最引人注目的是糖蛋白相关血型A活性的消失。对负责合成血型A决定簇的酶的测定表明，这种糖基转移酶活性在肿瘤组织中大大降低。半乳糖基转移酶和岩藻糖基转移酶在肿瘤组织中也显着降低，而另一种半乳糖基转移酶和唾液酸转移酶的水平不变。正常组织和肿瘤组织中的糖苷酶活性相似。结果表明，糖蛋白生物合成的改变发生在肿瘤形成过程中，导致在一个修改的膜糖蛋白的组成，这些变化可能是一个负责糖蛋白合成的酶的水平降低的反映。
Membrane glycopeptides were examined in human colonic adenocarcinoma and normal colonic mucosa. The carbohydrates of membrane glycopeptides were found to be markedly reduced in tumor tissue and the relative proportions of the various sugars were altered. Although all of the sugars were lower in tumor tissue when compared to the adjacent normal mucosa, galactosamine, fucose, and sialic acid were more significantly reduced. Examination of the blood group activity and lectin-binding properties of membrane glycopeptides revealed that specific carbohydrate structures had changed in the tumor tissue. Most striking of these changes was the disappearance of glycoprotein-associated blood group A activity. Assay of the enzyme responsible for synthesis of the blood group A determinant showed that this glycosyltransferase activity was greatly diminished in tumor tissue. A galactosyltransferase and a fucosyltransferase were also significantly lower in the tumor tissue whereas the levels of another galactosyltransferase and a sialyltransferase were unaltered. Glycosidase activities in the normal and tumor tissues were similar. The results show that an alteration in glycoprotein biosynthesis occurred during tumorigenesis that resulted in a modified membrane glycoprotein composition and that these changes are probably a reflection of reduced levels of the enzymes responsible for glycoprotein synthesis.