putrescine ~20-30: spermidine ~6-7 mM
||Bacteria Escherichia coli
||Theillet FX et al., Physicochemical properties of cells and their effects on intrinsically disordered proteins (IDPs). Chem Rev. 2014 Jul 9 114(13):6661-714. doi: 10.1021/cr400695p p.6664 left column bottom paragraphPubMed ID24901537
|| Tabor CW, Tabor H. Polyamines in microorganisms. Microbiol Rev. 1985 Mar49(1):81-99.PubMed ID3157043
||P.6664 left column bottom paragraph: "Putrescine and spermidine are generally found at high concentrations in Gram-negative bacteria such as E. coli, where spermine is absent. Studies in E. coli reported concentrations of ∼20–30 mM for putrescine and ∼6–7 mM for spermidine (primary source)."