Document Detail

LC/ESI/MS method development for the analysis of hepatotoxic cyclic peptide microcystins in animal tissues.
MedLine Citation:
PMID:  16626770     Owner:  NLM     Status:  MEDLINE    
Microcystins (MCYSTs) are a family of related cyclic heptapeptides produced by several genera and species of blue-green algae (cyanobacteria). MCYSTs are potent and specific inhibitors of the serine threonine family of protein phosphatases, especially PP1 and PP2A. MCYSTs inhibit a liver's protein phosphatase by forming a covalent linkage between MCYSTs' Mdha residue and the phosphatase's cysteine residue. Due to the covalent linkage, analysis of MCYSTs in animal tissues has been limited to determination of unbound MCYST concentration. The MMPB (2-methyl-3-methoxy-4-phenylbutyric acid) oxidation procedure allows for the detection of total MCYST burden by releasing the carboxylic acid MMPB from MCYST's Adda amino acid. An internal standard 4-phenylbutyric acid (4PB) accounts for losses during the method. LC/MS conditions were developed using a ThermoFinnigan LCQDuo ion trap in negative electrospray ionization (ESI). Since both compounds produce the [M-H](-) ion, analysis occurs in selected ion monitoring (SIM) mode for both MMPB (m/z 207.1) and 4PB (m/z 163.1). Complete oxidation of MCYST-LR in liver tissues occurs in 3h. A solid phase extraction (SPE) cartridge removes MMPB and 4PB from the oxidant solution. The process efficiency for the SPE procedure is only 51.3%; however, suppression experiments indicate a 41.8% loss in signal strength due to matrix interferences. Therefore, the extraction efficiency for the SDB-XC cartridge procedure is 93.1%. This research has been successful in developing an LC/MS method for the analysis of total MCYST burden in animal tissues.
Jennifer L Ott; Wayne W Carmichael
Publication Detail:
Type:  Journal Article     Date:  2006-04-19
Journal Detail:
Title:  Toxicon : official journal of the International Society on Toxinology     Volume:  47     ISSN:  0041-0101     ISO Abbreviation:  Toxicon     Publication Date:  2006 Jun 
Date Detail:
Created Date:  2006-05-29     Completed Date:  2006-08-08     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  1307333     Medline TA:  Toxicon     Country:  England    
Other Details:
Languages:  eng     Pagination:  734-41     Citation Subset:  IM    
Department of Biological Sciences, Wright State University, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA.
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MeSH Terms
Bacterial Toxins / analysis*,  toxicity
Benzoxazoles / chemistry
Chromatography, Liquid / methods*
Enzyme Inhibitors / chemistry
Liver / drug effects*
Maleimides / chemistry
Molecular Structure
Peptides, Cyclic / analysis*,  toxicity*
Spectrometry, Mass, Electrospray Ionization / methods*
Tissue Distribution
Reg. No./Substance:
0/5-maleimidyl-2-(m-methylphenyl)benzoxazol; 0/Bacterial Toxins; 0/Benzoxazoles; 0/Enzyme Inhibitors; 0/Maleimides; 0/Peptides, Cyclic

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