Isolation, identification and immunosuppressive activity of a new IMM-125 metabolite from human liver microsomes. Identification of its cyclophilin A-IMM-125 metabolite complex by nanospray tandem mass spectrometry.
The isolation from human liver microsomes and identification by electrospray mass spectrometry and tandem mass spectrometry of a new metabolite of IMM-125 resulting from the biotransformation of the amino acid 1 vinylic methyl group to a carboxylic acid, called the IMM-125-COOH metabolite, is described. It was found that the complex of this new metabolite with cyclophilin A is formed less easily than the corresponding cyclophilin A-IMM-125-CH2OH main metabolite and cyclophilin A-IMM-125 complexes. However, when formed, the IMM-125-COOH metabolite-cyclophilin A complex requires more collision-induced dissociation (CID) to dissociate the complex than the complexes formed with the two other ligands. The nanospray tandem mass spectrum of the IMM-125-COOH metabolite-cyclophilin A complex (m/z 1755) gives rise to cyclophilin A-ligand complexes of m/z 1751 by elimination of CO2 and of m/z 1749 by loss of CO2 and H2O or glycerol. Since immunosuppressive activity is known to be dependent on the formation of a binary complex between cyclophilin A and the drug and since the target for the binary complex was found to be the calcium- and calmodulin-dependent protein phosphatase, calcineurin, it could be interesting to measure for structurally related immunosuppressive drugs the CID energy necessary to dissociate the binary complexes in order to evaluate whether a correlation with the phosphatase activity could be derived.
Lhoëst
G J
GJ
Department of Pharmaceutical Sciences-UCL Pharmacokinetics and Metabolism Unit-FATC Laboratory of Mass Spectrometry, Brussels, Belgium. lhoest@fatc.ucl.ac.be
de Jong
A P
AP
Meiring
H D
HD
Maton
N
N
Latinne
D
D
Verbeeck
R K
RK
Otte
J B
JB
Zurini
M
M
D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid; D003524:Cyclosporins / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology; D006801:Humans; D007166:Immunosuppressive Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D066298:In Vitro Techniques; D007202:Indicators and Reagents; D008099:Liver / Q000737:chemistry; D013058:Mass Spectrometry; D008862:Microsomes, Liver / Q000737:chemistry / Q000378:metabolism*; D009504:Neutrophils / Q000187:drug effects / Q000276:immunology; D019696:Peptidylprolyl Isomerase / Q000737:chemistry*
D003524:Cyclosporins; C082770:IMM 125; D007166:Immunosuppressive Agents; D007202:Indicators and Reagents; D019696:Peptidylprolyl Isomerase