Cellular detoxification of tripeptidyl aldehydes by an aldo-keto reductase

• Published in: The Journal of biological chemistry 1993-03, Vol.268 (8), p.5894-5898
• Main Authors: INOUE, S, SHARMA, R. C, SCHIMKE, R. T, SIMONI, R. D
• Format: Article
• Language: English
• Subjects: Alcohol Oxidoreductases - metabolism; aldo-keto reductase; Amino Acid Sequence; Animals; Biological and medical sciences; Cell physiology; Cells, Cultured; CHO Cells; Cricetinae; Cytokinins - metabolism; detoxification; Drug Resistance; Effects of physical and chemical agents; enzymatic activity; Fundamental and applied biological sciences. Psychology; Humans; Leupeptins - antagonists & inhibitors; Leupeptins - toxicity; Molecular and cellular biology; Molecular Sequence Data; N-acetyl-leucyl-leucyl-norleucinal; Oligopeptides - antagonists & inhibitors; Oligopeptides - toxicity; Protease Inhibitors - metabolism; Protease Inhibitors - toxicity; resistant; tripeptidyl aldehyde
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/s0021-9258(18)53404-9

Calpain inhibitor I, N-acetyl-leucyl-leucyl-norleucinal (ALLN), a cell-permeable synthetic tripeptide with an aldehyde at its C terminus specifically inhibits the activity of cysteine proteases. Since the regulated degradation of 3-hydroxy-3-methylglutaryl-CoA reductase in Chinese hamster ovary (CHO) cells is blocked by ALLN and ALLN has a cytotoxic effect on cells, we attempted to isolate ALLN-resistant cells that overproduce an ALLN-sensitive protease(s). However, we obtained an ALLN-resistant cell line that overproduced P-glycoprotein (Sharma, R. C., Inoue, S., Roitelman, J., Schimke, R. T., and Simoni, R. D. (1992) J. Biol. Chem. 267, 5731-5734). To circumvent the multidrug resistance (MDR) phenotype during selection, we have stepwise selected an ALLN-resistant cell line of CHO cells in the presence of verapamil, a competitive inhibitor of P-glycoprotein. These non-MDR ALLN-resistant cells overexpress a 35-kDa protein and have increased aldo-keto reductase activity. Partial amino acid sequences of the 35-kDa protein are highly homologous to members of the aldo-keto reductase superfamily. The aldo-keto reductases are NADPH-dependent oxidoreductases and catalyze reduction of a wide range of carbonyl compounds such as aldehydes, sugars, and ketones. Our findings support the concept that a physiological function for aldo-keto reductases may be detoxification.