- α-methyl polyamines: Efficient synthesis and tolerance studies in vivo and in vitro. First evidence for dormant stereospecificity of polyamine oxidase
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Efficient syntheses of metabolically stable α-methylspermidine 1, α-methylspermine 2, and bis-α,α-methylated spermine 3 starting from ethyl 3-aminobutyrate are described. The biological tolerance for these compounds was tested in wild-type mice and transgenic mice carrying the metallothionein promoter-driven spermidine/spermine N1- acetyltransferase gene (MT-SSAT). The efficient substitution of natural polyamines by their derivatives was confirmed in vivo with the rats harboring the same MT-SSAT transgene and in vitro with the immortalized fibroblasts derived from these animals. Enantiomers of previously unknown 1-amino-8-acetamido-5-azanonane dihydrochloride 4 were synthesized starting from enantiomerically pure (R)- and (S)-alaninols. The studies with recombinant human polyamine oxidase (PAO) showed that PAO (usually splits achiral substrates) strongly favors the (R)-isomer of 4 that demonstrates for the first time that the enzyme has hidden potency for stereospecificity.
- J?rvinen, Aki J.,Cerrada-Gimenez, Marc,Grigorenko, Nikolay A.,Khomutov, Alex R.,Veps?l?inen, Jouko J.,Sinervirta, Riitta M.,Kein?nen, Tuomo A.,Alhonen, Leena I.,J?nne, Juhani E.
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p. 399 - 406
(2007/10/03)
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- α-Methyl polyamines: Metabolically stable spermidine and spermine mimics capable of supporting growth in cells depleted of polyamines
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In order to assess the tolerance of the target enzyme spermine synthase for α-substituents on the aminopropyl moiety of the substrate spermidine, 1- methylspermidine (MeSpd, 2) was synthesized. It was determined that MeSpd is a poor substrate for spermine synthase and is not a substrate for spermidine N1-acetyltransferase, suggesting that α-methylated polyamines might be metabolically stable and therefore useful tools for studying polyamine effects in intact cells. On the basis of initial cellular results with 2, 1- methylspermine (MeSpm, 3) and 1,12-dimethylspermine (Me2Spm, 4) were also synthesized. When added to cells (L1210, SV-3T3, or HT29) depleted of both putrescine and spermidine by prior treatment with α- (difluoromethyl)ornithine (DFMO), these α-methylated polyamines were able to restore cell growth to that observed in the absence of DFMO. In accord with the enzyme data noted above, metabolic studies indicated a slow conversion of 2 to 3, but no metabolism of 4 in these cells. It was concluded from these results that the α-methylated polyamines are able to substitute for the natural polyamines spermidine and spermine in critical biochemical processes which involve polyamines for continued cell growth. In accord with the hypothesis, preliminary data indicate that MeSpd and Me2Spm are as effective as spermidine and spermine, respectively, in promoting the conversion of B- DNA to Z-DNA.
- Lakanen,Coward,Pegg
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p. 724 - 734
(2007/10/02)
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