Kano T, Sakai M, Muramatsu M
Department of Biochemistry, University of Tokyo Faculty of Medicine, Japan.
Cancer Res. 1987 Nov 1;47(21):5626-30.
We have used a rat glutathione S-transferase P (GST-P) complementary DNA as a probe to screen a human placenta complementary DNA library constructed in the lambda gt11 vector. One of the positive clones contained the complete coding region (630 base pair) and the entire 3'-noncoding region (78 base pair) of the putative human glutathione S-transferase pi (GST-pi) subunit mRNA. From the nucleotide sequence we deduced the complete amino acid sequence of the GST-pi subunit. It contained 209 amino acids with the relative molecular mass of Mr 23,224. Comparison of the amino acid sequences between GST-pi and GST-P subunits suggests that they are the corresponding enzymes in these species. GST-pi and GST-P both consist of 209 amino acids and differ in only 30 amino acids (85.6% homology). The difference in amino acid composition can explain the large difference in isoelectric point between GST-pi subunit (pI 5.5) and GST-P subunit (pI 6.9). The expression of GST-pi mRNA in some normal and cancerous tissues, including some hepatoma cell lines, hepatoma, and colon carcinoma specimens was determined using complementary DNA as a probe. The results indicate that the mode of the expression of GST-pi in humans is different from that of GST-P in rats.
我们用大鼠谷胱甘肽S-转移酶P（GST-P）互补DNA作为探针，筛选构建于λgt11载体的人胎盘互补DNA文库。其中一个阳性克隆包含推定的人谷胱甘肽S-转移酶π（GST-π）亚基mRNA的完整编码区（630个碱基对）和整个3'-非编码区（78个碱基对）。从核苷酸序列我们推导了GST-π亚基的完整氨基酸序列。它包含209个氨基酸，相对分子质量为Mr 23,224。GST-π和GST-P亚基之间氨基酸序列的比较表明它们是这些物种中的相应酶。GST-π和GST-P均由209个氨基酸组成，仅在30个氨基酸上不同（同源性为85.6%）。氨基酸组成的差异可以解释GST-π亚基（pI 5.5）和GST-P亚基（pI 6.9）之间等电点的巨大差异。使用互补DNA作为探针测定了GST-π mRNA在一些正常和癌组织中的表达，包括一些肝癌细胞系、肝癌和结肠癌标本。结果表明，GST-π在人类中的表达模式与GST-P在大鼠中的表达模式不同。
