Trakshel G M, Maines M D
Department of Biophysics, University of Rochester School of Medicine, NY 14642.
Biochem J. 1988 May 15;252(1):127-36. doi: 10.1042/bj2520127.
We have developed chromatographic and mathematical protocols that allowed the high resolution of glutathione S-transferase (GST) subunits, and the identification of a previously unresolved GST monomer in rat kidney cytosol; the monomer was identified tentatively as subunit 6. Also, an aberrant form of GST 7-7 dimer appeared to be present in the kidney. This development was utilized to illustrate the response of rat kidney GST following cis-platinum treatment in vivo. Rat kidney cytosol was separated into three 'affinity families' of GST activity after elution from a GSH-agarose matrix. The affinity peaks were characterized by quantitative differences in their subunit and dimeric compositions as determined by subsequent chromatography on a cation-exchange matrix and specific activity towards substrates. By use of these criteria, the major GST dimers of affinity peaks were tentatively identified. The major GST dimers in peak I were GST 1-1 and 1-2, in affinity peak II it was GST 2-2, and in peak III they were GST 3-3 and 7-7. GST 3-6 and/or 4-6, which have not been previously resolved in kidney cytosol, were also present in peak II. Alterations in the kidney cytosolic GST composition of male rats were detected subsequent to the administration of cis-platinum (7.0 mg/kg subcutaneously, 6 days). This treatment caused a pronounced alteration in the GST profile, and the pattern of alteration was markedly different from that reported for other chemicals in the kidney or in the liver. In general, the cellular contents of the GSTs of the Alpha and the Mu classes decreased and increased respectively. It is postulated that the decrease in the Alpha class of GSTs by cis-platinum treatment may be related to renal cortical damage and the loss of GSTs in the urine. The increase in the Mu class of GSTs could potentially stem from a lowered serum concentration of testosterone; the latter is a known effect of cis-platinum treatment.
我们已经开发出了色谱和数学方法，能够对谷胱甘肽S-转移酶（GST）亚基进行高分辨率分析，并鉴定出大鼠肾细胞溶质中一种先前未解析的GST单体；该单体初步鉴定为亚基6。此外，在肾脏中似乎存在一种异常形式的GST 7-7二聚体。利用这一进展来阐明大鼠肾脏GST在体内顺铂治疗后的反应。从谷胱甘肽琼脂糖基质洗脱后，大鼠肾细胞溶质被分离为三个GST活性的“亲和家族”。通过随后在阳离子交换基质上的色谱分析以及对底物的比活性，确定了亲和峰在亚基和二聚体组成上的定量差异，以此对亲和峰进行表征。根据这些标准，初步鉴定了亲和峰中的主要GST二聚体。峰I中的主要GST二聚体是GST 1-1和1-2，亲和峰II中的是GST 2-2，峰III中的是GST 3-3和7-7。在肾脏细胞溶质中先前未解析的GST 3-6和/或4-6也存在于峰II中。在皮下注射顺铂（7.0 mg/kg，6天）后，检测到雄性大鼠肾脏细胞溶质中GST组成的变化。这种处理导致GST谱明显改变，且改变模式与肾脏或肝脏中其他化学物质报道的模式明显不同。一般来说，α类和μ类GST的细胞含量分别减少和增加。据推测，顺铂处理导致α类GST减少可能与肾皮质损伤以及尿液中GST的丢失有关。μ类GST的增加可能潜在地源于睾酮血清浓度降低；后者是顺铂治疗的已知效应。
