Biomaterial Database

Detection of inhibition of 5-aminoimidazole-4-carboxamide ribotide transformylase by thioinosinic acid and azathioprine by a new colorimetric assay. 1990

T Ha, and S L Morgan, and W H Vaughn, and I Eto, and J E Baggott

Department of Nutrition Sciences, University of Alabama, Birmingham 35294.

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.

UI	MeSH Term	Description	Entries
D007291	Inosine Monophosphate	Inosine 5'-Monophosphate. A purine nucleotide which has hypoxanthine as the base and one phosphate group esterified to the sugar moiety.	IMP,Inosinic Acid,Ribosylhypoxanthine Monophosphate,Inosinic Acids,Sodium Inosinate,Acid, Inosinic,Acids, Inosinic,Inosinate, Sodium,Monophosphate, Inosine,Monophosphate, Ribosylhypoxanthine
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D007963	Leukocytes, Mononuclear	Mature LYMPHOCYTES and MONOCYTES transported by the blood to the body's extravascular space. They are morphologically distinguishable from mature granulocytic leukocytes by their large, non-lobed nuclei and lack of coarse, heavily stained cytoplasmic granules.	Mononuclear Leukocyte,Mononuclear Leukocytes,PBMC Peripheral Blood Mononuclear Cells,Peripheral Blood Human Mononuclear Cells,Peripheral Blood Mononuclear Cell,Peripheral Blood Mononuclear Cells,Leukocyte, Mononuclear
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008817	Mice, Mutant Strains	Mice bearing mutant genes which are phenotypically expressed in the animals.	Mouse, Mutant Strain,Mutant Mouse Strain,Mutant Strain of Mouse,Mutant Strains of Mice,Mice Mutant Strain,Mice Mutant Strains,Mouse Mutant Strain,Mouse Mutant Strains,Mouse Strain, Mutant,Mouse Strains, Mutant,Mutant Mouse Strains,Mutant Strain Mouse,Mutant Strains Mice,Strain Mouse, Mutant,Strain, Mutant Mouse,Strains Mice, Mutant,Strains, Mutant Mouse
D002645	Chickens	Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.	Gallus gallus,Gallus domesticus,Gallus gallus domesticus,Chicken
D003124	Colorimetry	Any technique by which an unknown color is evaluated in terms of standard colors. The technique may be visual, photoelectric, or indirect by means of spectrophotometry. It is used in chemistry and physics. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
D005260	Female		Females
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000217	Acyltransferases	Enzymes from the transferase class that catalyze the transfer of acyl groups from donor to acceptor, forming either esters or amides. (From Enzyme Nomenclature 1992) EC 2.3.	Acyltransferase