Delannoy P, Pelczar H, Vandamme V, Verbert A
Laboratoire de Chimie Biologique (Unité Mixte de Recherche du CNRS n. 111), Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France.
Glycoconj J. 1993 Feb;10(1):91-8. doi: 10.1007/BF00731192.
We have investigated the activity of CMP-Neu5Ac:Gal beta 1-3GalNAc alpha-2,3-sialyltransferase (EC 2.4.99.4) in FR3T3 cells transformed by the Ha-ras oncogene in which we have previously demonstrated the higher expression of the beta-galactosidase alpha-2,6-sialyltransferase (EC 2.4.99.1) [21]. We demonstrate that the presence of the activated ras gene decreases the activity of this specific alpha-2,3-sialyltransferase fourfold. According to the kinetic parameters and to mixing experiments, we can assume that this decreased enzymatic activity reflects a decrease in the number of active O-glycan alpha-2,3-sialyltransferase polypeptides in ras-transformed cells. However, no change in the binding of Peanut agglutinin was observed on the cell surface of ras-transformed FR3T3 suggesting that no change in the sialylation of O-glycan core 1 appeared in these cells, although the activity of the alpha-2,3-sialyltransferase was decreased.
我们研究了CMP-唾液酸：β-半乳糖1-3-N-乙酰半乳糖胺α-2,3-唾液酸转移酶（EC 2.4.99.4）在被Ha-ras癌基因转化的FR3T3细胞中的活性，我们之前已证实在这些细胞中β-半乳糖苷酶α-2,6-唾液酸转移酶（EC 2.4.99.1）表达较高[21]。我们证明激活的ras基因的存在使这种特定的α-2,3-唾液酸转移酶的活性降低了四倍。根据动力学参数和混合实验，我们可以假定这种酶活性的降低反映了ras转化细胞中活性O-聚糖α-2,3-唾液酸转移酶多肽数量的减少。然而，在ras转化的FR3T3细胞表面未观察到花生凝集素结合的变化，这表明尽管α-2,3-唾液酸转移酶的活性降低，但这些细胞中O-聚糖核心1的唾液酸化没有变化。
