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The measurement of gamma-glutamyl hydrolase (conjugase) activity in rat brain

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Abstract

An assay using the artificial substrate, 2,4-diamino-10-methyl-pteroylglutamyl-gamma-glutamate (MTX-G1), was developed to measure gamma-glutamyl hydrolase (conjugase), which hydrolyzes folylpolyglutamates. This assay allows us to: 1) measure conjugase for the first time in rat brain and 2) measure conjugase in a reliable, sensitive and inexpensive manner. The MTX-binding assay results were compared to samples analyzed by HPLC and found to vary by only 13%. The artificial substrate, MTX-G1, had a lower rate of hydrolysis than pteroylglutamyl-gamma-glutamate (Pte-G2), 70.7±0.64 and 92.6±0.22 nmoles/hr/mg protein respectively. Conjugase was semi-purified 24 fold in H2O and found to have a pH optimum of 5.0.

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Author notes

  1. Dean M. Hartley

    Present address: Dept. of Neurology, Stanford University, 94305, Stanford, CA, 94305

  2. Peggy A. Bradshaw

    Present address: Stanford University Blood Center, 800 Welch Road, 94304, Palo Alto, CA, 94304

Authors and Affiliations

  1. Neurology Research Laboratory, Childrens Hospital of Los Angeles, Los Angeles, USA

    S. Robert Snodgrass

  2. Depart. of Pediatrics and Neurology, University of Southern California, California, USA

    S. Robert Snodgrass

Authors
  1. Dean M. Hartley
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  2. S. Robert Snodgrass
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  3. Peggy A. Bradshaw
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Hartley, D.M., Snodgrass, S.R. & Bradshaw, P.A. The measurement of gamma-glutamyl hydrolase (conjugase) activity in rat brain. Neurochem Res 13, 147–151 (1988). https://doi.org/10.1007/BF00973326

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  • DOI: https://doi.org/10.1007/BF00973326

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