Metabolism of small antimicrobial β2,2-amino acid derivatives by murine liver microsomes

  • Terkel HansenEmail author
  • Morten K. Moe
  • Trude Anderssen
  • Morten B. Strøm
Original Paper


We have investigated the in vitro metabolism of three small antimicrobial β2,2-amino acid derivatives (M w < 500) that are highly potent against methicillin resistant Staphylococcus aureus, and are among the first compounds designed from small cationic antimicrobial peptides with potential for oral administration. The β2,2-amino acid derivatives are virtually completely resistant against degradation by proteases, and to further explore their drug potential, we have investigated the hepatic Phase I metabolism of this class of antimicrobial compounds. The β2,2-amino acid derivatives were incubated with murine liver microsomes and the metabolites analyzed semi-quantitatively by HPLC–MS and qualitatively by ultra performance liquid chromatography coupled to a tandem mass spectrometer which enabled identification of the metabolites by careful interpretation of the collision activated dissociation spectra. The study shows that sterically hindered β2,2-amino acid derivatives that otherwise are stable against proteolytic degradation underwent Phase I metabolism and were oxidized to a number of different metabolites depending on the structure of the β2,2-amino acid side-chains.


In vitro metabolism Antimicrobial β2,2-amino acid derivatives AMPs Scaffold Phase I metabolism 



Cationic antimicrobial peptide


Base peak


Collision activated dissociation


Cone voltages


Cytochrome P450 enzyme


Particle diameter


Electrospray ionization


High performance liquid chromatography


Internal standard


Limit of detection


Limit of quantification


Minimal inhibitory concentration


Methylene naphthalene


Methicillin resistant Staphylococcus aureus


Methicillin resistant Staphylococcus epidermidis


Mass spectrometry


Nicotinamide adenine dinucleotide phosphate


Neutral loss


Quadrupole time of flight


Human erythrocytes


Reverse phase


Standard error of the mean


Single-ion recording


Time of flight


Retention time


Ultra performance liquid chromatography


Ultra violet


Volume standard



We thank Dr. Jack Bruun for technical assistance with running the Q-ToF experiments as well as Dr. Espen Hansen for help with obtaining the HRMS spectra.


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Copyright information

© Springer-Verlag France 2012

Authors and Affiliations

  • Terkel Hansen
    • 1
    • 4
    Email author
  • Morten K. Moe
    • 2
    • 3
  • Trude Anderssen
    • 1
  • Morten B. Strøm
    • 1
  1. 1.Department of Pharmacy, Faculty of Health SciencesUniversity of TromsøTromsøNorway
  2. 2.FRAM Centre (High North Research Centre for Climate and the Environment)Norwegian Institute for Air ResearchTromsøNorway
  3. 3.Department of Multidisciplinary Laboratory Medicine and Medical BiochemistryAkershus University HospitalLørenskogNorway
  4. 4.Leibniz-Institut für Analytische Wissenschaften – ISAS – e.V.DortmundGermany

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