The brown gene of Drosophila melanogaster is required for deposition of pteridine pigments in the compound eye and other tissues. We isolated a ca. 150-kilobase region including brown by microdissection and chromosome walking using cosmids. Among the cDNAs identified by hybridization to the cosmids, one class hybridized to a genomic region that is interrupted in two brown mutants, bw and In(2LR...

SOME ASPECTS OP PTERIDINE BIOSYNTHESIS IN AMPHIBIANS by Hamilton Lee Stackhouse Bright fluorescing unconjugated pteridines have been extracted from amphibians; yet the biological function of these compounds in vertebrates is not completely understood. There is some evidence, indicating that they can act as pigments, co-factors, and growthpromoting substances. Pteridine biosynthesis is unknown b...

In the title compound, [Co(C8H5N5O3)(C12H8N2)(H2O)]·3H2O, a tridentate 2-amino-7-methyl-4-oxidopteridine-6-carboxyl-ate ligand, a bidentate ancillary 1,10-phenanthroline (phen) ligand and a water mol-ecule complete a distorted octa-hedral geometry around the Co(II) atom. The pterin ligand forms two chelate rings. The phen and pterin ring systems are nearly perpendicular [dihedral angle = 85.15 ...

From a mutagenized population of wild type Leishmania donovani promastigotes, a clone was isolated in a single step by virtue of its resistance to 1 mM methotrexate, a potent inhibitor of dihydrofolate reductase. This methotrexate-selected cell line, MTXA5, was cross-resistant to aminopterin but just as sensitive to growth inhibition caused by pyrimethamine, trimethoprim, and cytotoxic purine a...

Folate, a water soluble B vitamin, is the generic term for both natural folylpolyglutamate derivatives (including methylfolate), and synthetic folic acid (pterolymonoglutamic acid, PteGlu). Folate consists of three molecular components; a pteridine ring, paraaminobenzoic acid and glutamic acid residues conjugated to the pteridine (Lucock, 2000). The natural form of folate found in food generall...

Catecholamines [dopamine, noradrenaline (norepinephrine), and adrenaline (epinephrine); CAs] are neurotransmitters in the central and peripheral nervous systems as well as hormones in the endocrine system. CAs in the brain play a central role in versatile functions as slow-acting neurotransmitters functioning in synaptic neurotransmission, modulating the effects of fast-acting neurotransmitters...

INTRODUCTION As well as folate (a conjugated pteridine) in plants and microorganisms, tetrahydrobiopterin (BH4, an unconjugated pteridine) in animals is also biosynthesized from GTP. So far three essential enzymes have been identified as being active in BH4 synthesis[1,2], while only the initial enzyme of the pathway is common with that of the folate pathway (Fig. 1). Since the cell level of BH...

The metabolism of the methyl group of 5-methyltetrahydrofolate was studied in rats in which cobalamin had been inactivated by exposure to nitrous oxide and in air-breathing control animals. Methylfolate labeled with [14C] in the methyl group and with [3H] in the pteridine-PABA portion was injected and the disappearance of [14C]H3- relative to [3H]folate was measured in liver. The half-time of t...

BACKGROUND Previous studies have provided evidence for the importance of platelet-derived nitric oxide (NO) for the regulation of hemostasis. Tetrahydrobiopterin (BH4) is an essential cofactor and regulator of NO synthase activity in the vasculature; however, it is as yet unknown whether platelets dispose over a functional BH4 synthesis. METHODS AND RESULTS We quantified mRNA expression of ge...

BACKGROUND Cutaneous leishmaniasis (CL) is a vector-borne parasitic disease characterized by the presence of one or more lesions on the skin that usually heal spontaneously after a few months. Most cases of CL worldwide occur in Southwest Asia, Africa and South America, and a number of cases have been reported among troops deployed to Afghanistan. No vaccines are available against this disease,...