Di Ilio C, Aceto A, Bucciarelli T, Angelucci S, Felaco M, Grilli A, Zezza A, Tenaglia R, Federici G
Istituti di Scienze Biochimiche, Facolta' di Medicina e Chirugia, Universita G. D'Annunzio, Chieti, Italia.
Carcinogenesis. 1991 Aug;12(8):1471-5. doi: 10.1093/carcin/12.8.1471.
Glutathione transferase (GST) activity in the cytosolic fractions of renal cortex tumour was found to be significantly lower (215 +/- 156 mU/mg) than that present in the corresponding non-tumour (466 +/- 278 mU/mg) tissues. Using the immunoblotting technique, glutathione transferase isoenzymes expression in both tumour and non-tumour kidney was investigated. Alpha and pi class glutathione transferases were the most abundant enzymes in non-tumour kidney and were expressed by all samples investigated. Immunofluorescence analysis indicated that the pi class enzymes are localized mainly in the distal convoluted tubules, whereas alpha class enzymes are localized in the proximal tubules. In the tumour moiety the alpha class GST appears to be absent or expressed at low level as compared with non-tumour samples. On the contrary, no significant differences in the expression of pi class GST were found in tumour as compared with non-tumour tissues. Mu class GST protein was detected in 12 of 26 samples tested. When present, mu class GST constitutes a few per cent of total GST protein. Immunofluorescence studies indicate that mu class GSTs are localized within the distal convoluted tubules. According to the electrophoretic mobility at least two different mu GST subunits (26.5 and 27.5 kd) were found. In one sample only the faster mu class GST subunit was present, two samples expressed both types of GST subunits, whereas nine samples expressed only the slower GST subunit. With the exception of one sample, a reduction of mu class GST expression was seen in tumour as compared with non-tumour tissues. The decrease of activity seen in the cytosolic fraction of tumour kidney must be ascribed mainly to a reduction or to a lack of expression of alpha class GST and to a lesser extent of mu class GST.
肾皮质肿瘤胞质部分的谷胱甘肽转移酶（GST）活性显著低于相应的非肿瘤组织（215±156 mU/mg），非肿瘤组织的该活性为466±278 mU/mg。采用免疫印迹技术，研究了肿瘤肾和非肿瘤肾中谷胱甘肽转移酶同工酶的表达。α类和π类谷胱甘肽转移酶是非肿瘤肾中含量最丰富的酶，所有检测样本均有表达。免疫荧光分析表明，π类酶主要定位于远曲小管，而α类酶定位于近端小管。与非肿瘤样本相比，肿瘤部分的α类GST似乎缺失或表达水平较低。相反，与非肿瘤组织相比，肿瘤中π类GST的表达没有显著差异。在26个检测样本中的12个中检测到了μ类GST蛋白。当存在时，μ类GST占总GST蛋白的百分之几。免疫荧光研究表明，μ类GST定位于远曲小管内。根据电泳迁移率，发现至少有两种不同的μGST亚基（26.5和27.5 kd）。在一个样本中仅存在较快的μ类GST亚基，两个样本表达了两种类型的GST亚基，而九个样本仅表达了较慢的GST亚基。除一个样本外，与非肿瘤组织相比，肿瘤中μ类GST的表达减少。肿瘤肾胞质部分活性的降低主要归因于α类GST表达的减少或缺失，以及μ类GST表达程度较低。
