The influence of ammonia and inhibition of the urea cycle by norvaline on orotic acid synthesis in five Polish Merino ewes was investigated. The sheep were exposed to 60 min of successive infusions of 0.9% NaCl, NH4Cl (20 mumol kg-1 min-1), and NH4Cl with DL-norvaline (10 mumol kg-1 min-1) solutions administered to the mesenteric vein. The average rate of orotic acid output, urea output and amm...

An attempt has been made to relate the effect of a drug on a metabolic pathway, pre sumed to be its locus of action, to the tumor-inhibitory activity of the drug. Azauridine was administered subcutaneously to mice with five different ascites tumors, and growth was measured by total ascites cell counts. Aliquots of ascites tumor cells were incubated with orotic acid-7-C14, and the C14O2evolved w...

A rapid, sensitive, and specific method for quantification of orotic acid from dried filter-paper urine samples is described. The method involves stable isotope dilution with 1,3-[15N2]orotic acid analysis by gas chromatography-mass spectrometry. The assay is sufficiently sensitive to be used with solvent extraction techniques commonly used for urinary organic acid analysis. Extraction efficien...

The complexes of orotic acid with Co(II), Ni(II), Fe(III), Cu(II), and Cd(II) were prepared and their stoichiometry were determined by elemental analysis. Co(II) and Ni(II) give complexes with orotic acid of 1:1 ratio whereas that of the remaining transition metals give complexes of 1:2 ratio. The stereochemistry of the studied metal complexes has been established by analyses of their electroni...

We describe procedures for determining cytosine and orotic acid in urine. We determine cytosine by cation-exchange analysis with either HCl or pH 5.2 buffer as eluent. Orotic acid is first separated by an anion-exchange separative procedure; after lyophilization, the product is subjected to "high-pressure" liquid chromatography for further separation and detection. We analyzed urine from normal...

In our preliminary report,,) we described that an oral administration of orotic acid to galactosemic patients resulted in a remarkable decrease of urinary galactose and in an improvement of galactose tolerance curve in addition to a noticeable improvement of clinical symptoms and signs of the patients. In this paper, the effect of orotic acid on galactose metabolism investigated in erythrocytes...

Orotic acid is an intermediate of the de novo pyrimidine biosynthesis that plays a crucial role in several nutraceutical supplements. In some microorganisms, blockage this pathway downstream dihydroorotate dehydrogenase (DHOD) leads to orotic accumulation. Here, Ashbya gossypii Agura3 auxotroph was shown accumulate and excrete (~1.5 g/L), trait further explored for production from raw substrate...

pharmacologically active substances (23). It is also recognized that the lung contains enzymatic systems capable of metabolizing foreign compounds (3, 11, 55), although their oi'erall importance is considered to be rather small (38). Nevertheless, the induction of aryl hydrocarbon hydroxylases in lung by polycyclic hydrocarbons and other compounds (11, 59†" 61)and the inhibition of this adapt...

cocci (Rogers, lW), Laetobaciuus cas& (Chattaway, lW), and Laclobaeiuus bulgcrricus, strain 09 (Wieland et d., 1950; Huff et d., 1950). Further studiea with L. bulgaricw, strain 09 have revealed that ureidosuccinic acid partially replacea that orotic acid ia also a nucleic acid pyrimidine a growth factor for one of the group C streptoprecursor in mammdim tissues. Studiea of orotic acid synthwia...