Detection of inhibition of 5-aminoimidazole-4-carboxamide ribotide transformylase by thioinosinic acid and azathioprine by a new colorimetric assay
| Autor: | W H Vaughn, Isao Eto, Sarah L. Morgan, Joseph E. Baggott, T Ha |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Hydroxymethyl and Formyl Transferases
Inosine monophosphate Ribonucleotide Metabolite Binding Competitive Biochemistry Peripheral blood mononuclear cell Phosphoribosylaminoimidazolecarboxamide Formyltransferase Autoimmune Diseases Mice chemistry.chemical_compound Inosine Monophosphate Azathioprine Animals Humans Molecular Biology chemistry.chemical_classification Thioinosinic acid biology Phosphoribosylaminoimidazolecarboxamide formyltransferase Cell Biology Thionucleotides Molecular biology Mice Mutant Strains Kinetics Enzyme Liver chemistry Enzyme inhibitor Leukocytes Mononuclear biology.protein Colorimetry Female Chickens Acyltransferases Research Article |
| Zdroj: | Biochemical Journal. 272:339-342 |
| ISSN: | 1470-8728 0264-6021 |
| DOI: | 10.1042/bj2720339 |
| Popis: | The colorimetric assay for 5-aminoimidazole-4-carboxamide ribotide (AICAR) transformylase (phosphoribosylamino-imidazolecarboxamide formyltransferase; EC 2.1.2.3) has been extensively modified. The modified assay is based upon the short-term permanganate oxidation of the folate product, tetrahydrofolate (H4folate) to p-aminobenzoyl glutamate (pABG). The modified assay was used to detect the transformylase activity in crude extracts of peripheral-blood mononuclear cells (PBMCs). Azathioprine and its metabolite, thioinosinic acid (tIMP), are competitive inhibitors (with respect to AICAR) of the chicken liver transformylase and the transformylase from PBMCs of the MRL/lpr mouse, an animal model of systemic autoimmune disease. The Ki values of tIMP and azathioprine for the chicken liver enzyme are 39 +/- 4 microM and 120 +/- 10 microM, whereas the Ki values for the enzyme from PBMCs of the MRL/lpr mouse are 110 +/- 20 microM and 90 +/- 14 microM respectively. The anti-inflammatory drugs ibuprofen and naproxen are also inhibitors of the transformylase. |
| Databáze: | OpenAIRE |
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