Mammalian class Sigma glutathione S-transferases: catalytic properties and tissue-specific expression of human and rat GSH-dependent prostaglandin D2 synthases

Ian R. Jowsey, Anne M. Thomson, Jack U. Flanagan, Paul R. Murdock, Gary B. T. Moore, David J. Meyer, Gregory J. Murphy, Stephen A. Smith, John D. Hayes

    Research output: Contribution to journalArticle

    87 Citations (Scopus)

    Abstract

    GSH-dependent prostaglandin D2 synthase (PGDS) enzymes represent the only vertebrate members of class Sigma glutathione S-transferases (GSTs) identified to date. Complementary DNA clones encoding the orthologous human and rat GSH-dependent PGDS (hPGDS and rPGDS, respectively) have been expressed in Escherichia coli, and the recombinant proteins isolated by affinity chromatography. The purified enzymes were both shown to catalyse specifically the isomerization of prostaglandin (PG) H2 to PGD2. Each transferase also exhibited GSH-conjugating and GSH-peroxidase activities. The ability of hPGDS to catalyse the conjugation of aryl halides and isothiocyanates with GSH was found to be less than that of the rat enzyme. Whilst there is no difference between the enzymes with respect to their Km values for 1-chloro-2,4-dinitrobenzene, marked differences were found to exist with respect to their Km for GSH (8mM versus 0.3mM for hPGDS and rPGDS, respectively). Using molecular modelling techniques, amino acid substitutions have been identified in the N-terminal domain of these enzymes that lie outside the proposed GSH-binding site, which may explain these catalytic differences. The tissue-specific expression of PGDS also varies significantly between human and rat; amongst the tissues examined, variation in expression between the two species was most apparent in spleen and bone marrow. Differences in catalytic properties and tissue-specific expression of hPGDS and rPGDS appears to reflect distinct physiological roles for class Sigma GST between species. The evolution of divergent functions for the hPGDS and rPGDS is discussed in the context of the orthologous enzyme from chicken.
    Original languageEnglish
    Pages (from-to)507-516
    Number of pages10
    JournalBiochemical Journal
    Volume359
    Issue number3
    DOIs
    Publication statusPublished - 1 Nov 2001

    Fingerprint Dive into the research topics of 'Mammalian class Sigma glutathione S-transferases: catalytic properties and tissue-specific expression of human and rat GSH-dependent prostaglandin D2 synthases'. Together they form a unique fingerprint.

    Cite this