Biomaterial Database

Structure-activity relationship of ligands of uracil phosphoribosyltransferase from Toxoplasma gondii. 1994

M H Iltzsch, and K O Tankersley

Department of Biological Sciences, University of Cincinnati, OH 45221-0006.

One hundred compounds were evaluated as ligands of Toxoplasma gondii uracil phosphoribosyltransferase (UPRTase, EC 2.4.2.9) by examining their ability to inhibit this enzyme in vitro. Inhibition was quantified by determining apparent Ki values for those compounds that inhibited T. gondii UPRTase by greater than 10% at a concentration of 2 mM. Five compounds (4-thiopyridine, 2-thiopyrimidine, trithiocyanuric acid, 1-deazauracil and 2,4-dithiouracil) bound to the enzyme better than two known substrates for T. gondii UPRTase, 5-fluorouracil and emimycin, which have antitoxoplasmal activity (Pfefferkorn ER, Exp Parasitol 44: 26-35, 1978; Pfefferkorn et al., Exp Parasitol 69: 129-139, 1989). In addition, several selected compounds were evaluated as substrates for T. gondii UPRTase, and it was found that 2,4-dithiouracil is also a substrate for this enzyme. On the basis of these data, a structure-activity relationship for the binding of ligands to T. gondii UPRTase was determined using uracil as a reference compound.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008024	Ligands	A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g., an antigen binding to an antibody, a hormone or neurotransmitter binding to a receptor, or a substrate or allosteric effector binding to an enzyme. Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex. (From Dorland, 27th ed)	Ligand
D010430	Pentosyltransferases	Enzymes of the transferase class that catalyze the transfer of a pentose group from one compound to another.
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D000981	Antiprotozoal Agents	Substances that are destructive to protozoans.	Schizonticides,Agents, Antiprotozoal
D013329	Structure-Activity Relationship	The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.	Relationship, Structure-Activity,Relationships, Structure-Activity,Structure Activity Relationship,Structure-Activity Relationships
D013379	Substrate Specificity	A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.	Specificities, Substrate,Specificity, Substrate,Substrate Specificities
D014122	Toxoplasma	A genus of protozoa parasitic to birds and mammals. T. gondii is one of the most common infectious pathogenic animal parasites of man.	Toxoplasma gondii,Toxoplasma gondius,Toxoplasmas,gondius, Toxoplasma
D014498	Uracil	One of four nucleotide bases in the nucleic acid RNA.
D015195	Drug Design	The molecular designing of drugs for specific purposes (such as DNA-binding, enzyme inhibition, anti-cancer efficacy, etc.) based on knowledge of molecular properties such as activity of functional groups, molecular geometry, and electronic structure, and also on information cataloged on analogous molecules. Drug design is generally computer-assisted molecular modeling and does not include PHARMACOKINETICS, dosage analysis, or drug administration analysis.	Computer-Aided Drug Design,Computerized Drug Design,Drug Modeling,Pharmaceutical Design,Computer Aided Drug Design,Computer-Aided Drug Designs,Computerized Drug Designs,Design, Pharmaceutical,Drug Design, Computer-Aided,Drug Design, Computerized,Drug Designs,Drug Modelings,Pharmaceutical Designs