with urease. A third minor metabolite was present in urine collected after intraperitoneal administration but remains unidentified. The quantitative distribution of pterin-dcarboxylic acid and urea in the 0-24 h urine samples is shown in Table 1. Fukushima & Nixon (1980) reported the degradation of [2-14C]pterin-6-carboxylic acid to 14C02 by the gut microorganisms of the rat. It is possible tha...

Earlier studies have indicated the marked resistance of two pronase endopeptidases to denaturation in high concentrations of urea or guanidine hydrochloride (Siegel, S., and Awad, W. M., Jr. (1973) d BioL Chem 248, 3233-3240). One component has only a single residue of lysine and the other has none. The consideration arose that lysine-containing peptide segments may be less stable than those co...

The roles of OmpC and OmpF in acidic resistance (AR) were examined. When ompC and ompF were deleted, AR was decreased. The decreased level of AR seen in the mutant that was deficient in ompC and ompF was elevated by the addition of glutamate, but not by the addition of arginine or lysine. The expression levels of adiA and cadB were diminished by the deletion of ompC and ompF, and the conversion...

A series of trials was conducted to determine the effects of supplemental rumen-protected methionine (RPMet) and lysine (RPLys) on nutrient metabolism and performance. In situ RPMet N disappearance was less than 4% following 48 h of incubation and was not affected (P greater than .05) by diet or resultant ruminal pH differences, indicating that RPMet was well protected from ruminal microbial de...

The system N transporter SN1 has been proposed to mediate the efflux of glutamine from cells required to sustain the urea cycle and the glutamine-glutamate cycle that regenerates glutamate and gamma-aminobutyric acid (GABA) for synaptic release. We now show that SN1 also mediates an ionic conductance activated by glutamine, and this conductance is selective for H(+). Although SN1 couples amino ...

Antibodies against gamma-aminobutyric acid (GABA)-glutaraldehyde-lysine were obtained by using a procedure based upon (i) a high yield of coupling of GABA to protein carriers, (ii) the reduction of the resulting immunoreactive double bonds, and (iii) a protocol of alternative immunizations using different immunogens having in common only the GABA-glutaraldehyde-lysine segment. This strategy led...

Crude metabolites of 21 of 60 fungal cultures isolated from some of the common cereals collected from different parts of India were found to be toxic. Of these toxin-producing fungi, 79% caused hepatic pathology of varying severity in mice. Serum glutamate pyruvate transaminase values and blood urea nitrogen were found to be high in such experimental animals.

N -Acetylglutamate (NAG) fulfils distinct biological roles in lower and higher organisms. In prokaryotes, lower eukaryotes and plants it is the first intermediate in the biosynthesis of arginine, whereas in ureotelic (excreting nitrogen mostly in the form of urea) vertebrates, it is an essential allosteric cofactor for carbamyl phosphate synthetase I (CPSI), the first enzyme of the urea cycle. ...

Protective role of Gycyrrhiza glabra rhizomes (roots) at three dose levels (100, 75, & 50 mg/kg/bw) against sublethaldose (300 mg/kg/bw) of acetaminophen (paracetamol) induced hepatorenal damage has been assessed in mice. Parameters of study were glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), billirubin, alkaline phosphatase (ALP) as liver function tests, crea...

Increased brain ammonia concentrations are a hallmark feature of several neurological disorders including congenital urea cycle disorders, Reye's syndrome and hepatic encephalopathy (HE) associated with liver failure. Over the last decade, increasing evidence suggests that hyperammonemia leads to alterations in the glutamatergic neurotransmitter system. Studies utilizing in vivo and in vitro mo...