A sensitive assay of GTP cyclohydrolase I activity in rat and human tissues using radioimmunoassay of neopterin
| Autor: | Toshio Horikoshi, Sadao Matsuura, Makoto Sawada, Takashi Sugimoto, Toshiharu Nagatsu, Masahiro Masada, Miki Akino |
|---|---|
| Rok vydání: | 1986 |
| Předmět: |
Male
GTP' GTP cyclohydrolase I Radioimmunoassay Biophysics Neopterin Biochemistry chemistry.chemical_compound Aminohydrolases medicine Animals Humans Tissue Distribution GTP Cyclohydrolase Molecular Biology chemistry.chemical_classification biology medicine.diagnostic_test Pteridines Brain Parkinson Disease Rats Inbred Strains Cell Biology Biopterin Molecular biology Enzyme assay Rats Enzyme chemistry Immunoassay biology.protein Alkaline phosphatase Caudate Nucleus |
| Zdroj: | Analytical Biochemistry. 154:361-366 |
| ISSN: | 0003-2697 |
| DOI: | 10.1016/0003-2697(86)90537-3 |
| Popis: | A highly sensitive and simple assay for the activity of GTP cyclohydrolase I (EC 3.5.4.16) was established using a newly developed radioimmunoassay. D-erythro-7,8-Dihydroneopterin triphosphate formed from GTP by GTP cyclohydrolase I was oxidized by iodine and dephosphorylated by alkaline phosphatase to D-erythro-neopterin, and quantified by a radioimmunoassay for D-erythro-neopterin. This method was highly sensitive and required only 0.2 mg of rat liver tissues for the measurement of the activity. It was reproducible and can be applied for the simultaneous assay of many samples. The activity of GTP cyclohydrolase I was measured in several rat tissues. For example, the enzyme activity in rat striatum (n = 5) was 13.7 +/- 1.5 pmol/mg protein per hour (mean +/- SE), and agreed well with those obtained by high-performance liquid chromatography with fluorescence detection. The activity in the autopsy human brains (caudate nucleus) was measured by this new method for the first time. The activity in the caudate nucleus from parkinsonian patients (n = 6) was 0.82 +/- 0.56 pmol/mg protein per hour which was significantly lower than the control value, 4.22 +/- 0.43 pmol/mg protein per hour (n = 10). |
| Databáze: | OpenAIRE |
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