title: Complex N-acetylation of triethylenetetramine.
abstract: Triethylenetetramine (TETA) is an efficient copper chelator that has versatile clinical potential. We have recently shown that spermidine/spermine-N(1)-acetyltransferase (SSAT1), the key polyamine catabolic enzyme, acetylates TETA in vitro. Here, we studied the metabolism of TETA in three different mouse lines: syngenic, SSAT1-overexpressing, and SSAT1-deficient (SSAT1-KO) mice. The mice were sacrificed at 1, 2, or 4 h after TETA injection (300 mg/kg i.p.). We found only N(1)-acetyltriethylenetetramine (N(1)AcTETA) and/or TETA in the liver, kidney, and plasma samples. As expected, SSAT1-overexpressing mice acetylated TETA at an accelerated rate compared with syngenic and SSAT1-KO mice. It is noteworthy that SSAT1-KO mice metabolized TETA as syngenic mice did, probably by thialysine acetyltransferase, which had a K(m) value of 2.5 ± 0.3 mM and a k(cat) value of 1.3 s(-1) for TETA when tested in vitro with the human recombinant enzyme. Thus, the present results suggest that there are at least two N-acetylases potentially metabolizing TETA. However, their physiological significance for TETA acetylation requires further studies. Furthermore, we detected chemical intramolecular N-acetyl migration from the N(1) to N(3) position of N(1)AcTETA and N(1),N(8)-diacetyltriethylenetetramine in an acidified high-performance liquid chromatography sample matrix. The complex metabolism of TETA together with the intramolecular N-acetyl migration may explain the huge individual variations in the acetylation rate of TETA reported earlier.
authors: Department of Medicine, Biocenter Kuopio, University of Eastern Finland, Kuopio, Finland.
authors: Marc
authors: M
authors: Cerrada-Gimenez
authors: Janne
authors: J
authors: Weisell
authors: Mervi T
authors: MT
authors: Hyvönen
authors: Myung Hee
authors: MH
authors: Park
authors: Leena
authors: L
authors: Alhonen
authors: Jouko
authors: J
authors: Vepsäläinen
authors: Tuomo A
authors: TA
authors: Keinänen
mesh_terms: D000107:Acetylation; D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002853:Chromatography, Liquid; D008099:Liver / Q000201:enzymology; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D014266:Trientine / Q000378:metabolism*; D000099228:Diamine N-Acetyltransferase
chemical_list: D000123:Acetyltransferases; D014266:Trientine; D000099228:Diamine N-Acetyltransferase