Metabolism of triethylenetetramine and 1,12-diamino-3,6,9-triazadodecane by the spermidine/spermine-N(1)-acetyltransferase and thialysine acetyltransferase.

Mervi T Hyvönen, Janne Weisell, Alex R Khomutov, Leena Alhonen, Jouko Vepsäläinen, Tuomo A Keinänen

Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute, Finland.

Drug metabolism and disposition: the biological fate of chemicals 2013 Jan

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Triethylenetetramine (TETA; Syprine; Merck Rahway, NJ), a drug for Wilson's disease, is a copper chelator and a charge-deficient analog of polyamine spermidine. We recently showed that TETA is metabolized in vitro by polyamine catabolic enzyme spermidine/spermine-N(1)-acetyltransferase (SSAT1) and by thialysine acetyltransferase (SSAT2) to its monoacetylated derivative (MAT). The acetylation of TETA is increased in SSAT1-overexpressing mice compared with wild-type mice. However, SSAT1-deficient mice metabolize TETA at the same rate as the wild-type mice, indicating the existence of another N-acetylase respons 2ible for its metabolism in mice. Here, we show that siRNA-mediated knockdown of SSAT2 in HEPG2 cells and in primary hepatocytes from the SSAT1-deficient or wild-type mice reduced the metabolism of TETA to MAT. By contrast, 1,12-diamino-3,6,9-triazadodecane(SpmTrien), a charge-deficient spermine analog, was an extremely poor substrate of human recombinant SSAT2 and was metabolized by SSAT1 in HEPG2 cells and in wild-type primary hepatocytes. Thus, despite the similar structures of TETA and SpmTrien, SSAT2 is the main acetylator of TETA, whereas SpmTrien is primarily acetylated by SSAT1.

Citation

Mervi T Hyvönen, Janne Weisell, Alex R Khomutov, Leena Alhonen, Jouko Vepsäläinen, Tuomo A Keinänen. Metabolism of triethylenetetramine and 1,12-diamino-3,6,9-triazadodecane by the spermidine/spermine-N(1)-acetyltransferase and thialysine acetyltransferase. Drug metabolism and disposition: the biological fate of chemicals. 2013 Jan;41(1):30-2