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R Kido

Publications and source records attributed to R Kido.

At least 19 recordsLinked to original sources
PubMed1995

Metabolic inter-organ relations by exercise of fed rat: carbohydrates, ketone body, and nitrogen compounds in splanchnic vessels.

Fed rats were exercised until exhaustion by almost 65% VO2max on a treadmill. In 2.5 min after the exercise, blood was collected from various vessels of the splanchnic bed. Metabolites, glucose, lactate, ketone body, and nitrogencompounds in the plasma, were measured. Glucose excretion from the liver was increased by exercise, but was not significant. The absorption by the kidney decreased to 30% by exercise. Lactate was highly absorbed by the kidney, lower limbs, and digestive tract by exercise. Exercise caused a 200-300% increase of the plasma beta-hydroxybutyrate, but the absorption by the kidney and the lower limbs was decreased. These data suggest that glucose is a good carbon source for the recovery, and that lactate is more useful than glucose, but ketone body is less effective at a very early recovery phase under fed condition. Amino acid balances in each organ except digestive tract were positive showing anabolic conditions of these organs even after exhaustive exercise at fed condition. Most amino acid concentrations in the plasma tended to decrease to 60-90% by exercise. Amino acids were excreted from the digestive tract, and were eventually absorbed by the liver in both rested and exercised rat. The digestive tract, therefore, seems to be a primary amino acids pool to supply them to the liver during the inter meal. Urea excretion from the liver was more than the absorbed ammonia showing that active deamination from amino acids was carrying on. The resulted carbon skeletons of the amino acids might be used for the gluconeogenesis in the liver.

Amino Acids↗
PubMed1995

Molecular cloning and sequencing of a cDNA encoding alanine-glyoxylate aminotransferase 2 from rat kidney.

Alanine-glyoxylate aminotransferase (AGT) 2 is a pyridoxal 5'-phosphate dependent, mitochondrial enzyme which, in the rat, is expressed at a high level in the kidney. The amino acid sequences of nine tryptic and seven CNBr peptides of the rat kidney AGT2 were determined. Three overlapping cDNAs encoding the AGT2 were cloned on the basis of its partial amino acid sequences by means of a polymerase chain reaction-based approach involving rat kidney poly(A)+ RNA. The complete cDNA sequence comprised 1,919 bases, and contained a 1,536-base open reading frame which encodes a polypeptide of 512 amino acid residues with a putative presequence consisting of 39 amino acid residues at the amino terminus, giving a precursor protein with a molecular mass of 57,150 Da. The sequence of AGT2 exhibits significant homology with neither peroxisomal AGT1 from human liver nor mitochondrial AGT1 from rat liver. However, the sequence of AGT2 exhibited 30.8, 29.2, and 27.1% identity with those of Escherichia coli 4-aminobutyrate aminotransferase, rat ornithine aminotransferase, and Pseudomonas cepacia 2,2-dialkylglycine decarboxylase, respectively. The active site sequences were also well conserved among these aminotransferases. AGT2, thus, is more similar to the other aminotransferases than to AGT1. The results suggest that the rat kidney AGT2 may play a biological role in amino acid metabolism distinct from that of AGT1.

Alanine Transaminase↗
PubMed1995

Tryptophan 2,3-dioxygenase in Saccharomyces cerevisiae.

The tryptophan pyrrole-ring cleavage enzyme (TPCE) was detected in the yeast Saccharomyces cerevisiae. TPCE activity existed constitutively and was markedly induced by culturing the cells in a medium containing 0.1% (w/v) L-tryptophan. We purified partially the enzyme from the L-tryptophan-induced cells by phospho-cellulose column chromatography. The partially purified enzyme was stimulated solely by L-ascorbic acid, a nonspecific reductant, suggesting that the yeast TPCE is not indoleamine 2,3-dioxygenase, but rather tryptophan 2,3-dioxygenase. The enzyme metabolized L-tryptophan preferentially, and D-tryptophan slightly. KCN and NaN3, exogenous ligands of heme, inhibited the enzyme activity drastically, indicating that yeast tryptophan 2,3-dioxygenase contains heme(s) in its active site. The optimal pH of the enzyme was 6.5. Upon two-dimensional polyacrylamide gel electrophoresis, a protein staining spot was identified that was induced by L-tryptophan and whose intensity changed in correlation with the tryptophan 2,3-dioxygenase activity after phospho-cellulose column chromatography. This protein, exhibiting a molecular weight of approximately 38,000 and an isoelectric point of approximately pH 8.0, may be identified as a subunit of yeast tryptophan 2,3-dioxygenase.

Azides↗
PubMed1994

DNA fragmentation during the programmed cell death in the chick limb buds.

Programmed cell death plays a crucial role in limb morphogenesis of amniote. So far, there has been no biochemical evidence found to support the fact that embryonic cell death is apoptosis. In this report, we show the oligo-nucleosomal ladder pattern of DNA obtained from interdigital tissues of chick leg buds, indicating that programmed cell death has some features that are common to those involved in apoptosis. Furthermore, cells exhibiting DNA fragmentation were detected by using a method of in situ end labeling of DNA breaks. The distribution pattern of those cells corresponded well to those of programmed-dead cells situated within the interdigital mesenchyme of the leg bud.

Animals↗
PubMed1994

Purification and amino- and carboxyl-terminal amino acid sequences of alanine-glyoxylate transaminase 1 from human liver.

In order to confirm the amino acid sequence predicted from the nucleotide sequence of cDNA and also to elucidate the intracellular localization and molecular evolution, human liver alanine-glyoxylate transaminase 1 (AGT1) was purified and subjected to partial amino acid sequence determination, with special attention to posttranslational modification. The enzyme was purified to homogeneity from the 10,000 x g supernatant of human liver homogenate. The purified enzyme showed only a single protein band at about 43 kDa on SDS-PAGE, indicating that it is a homodimer of two identical subunits, because the native enzyme has a molecular mass of about 80 kDa. Both the amino- and carboxyl-terminal peptides of the enzyme were isolated from a cyanogen bromide digest of the S-carboxyl-methylated protein and subjected to amino acid sequence determination. The alpha-amino group of the amino-terminal peptide was shown to be blocked by an acetyl group. The carboxyl-terminal sequence contained a putative N-glycosylation sequence (-Asn-Ala-Thr-), the only one present in the whole molecule, but this sequence was normally determined, indicating that the enzyme is not N-glycosylated. Purdue et al. [J. Cell Biol. 111, 2341-2351 (1990)] have reported that Pro-11, Gly-170, and Ile-340 in normal human AGT1 were replaced by Leu, Arg, and Met, respectively, in a patient with primary hyperoxaluria type 1. We confirmed that residue-11 was Pro. Both the amino- and carboxyl-terminal sequences of the enzyme showed extensive similarity with those of rat liver mitochondrial serine-pyruvate aminotransferase and the small chain of hydrogenase from a thermophilic unicellular cyanobacterium, Synechococcus PCC 6716.(ABSTRACT TRUNCATED AT 250 WORDS)

Alanine Transaminase↗
PubMed1993

Autosomal codominant inheritance and Japanese incidence of deficiency of OKT4 epitope with lack of reactivity resulting from conformational change.

A large Japanese family in which some members were homozygous or heterozygous for OKT4 epitope deficiency was studied. Homozygotes, heterozygotes, and normal individuals were identified by differences in the number of OKT4 epitopes on the surfaces of lymphocytes. This deficiency was transmitted as an autosomal codominant trait. The internalization of CD4 molecules and the production of IL-2 by lymphocytes of these subjects were examined. The OKT4 epitope was not needed for internalization of CD4 molecules, and IL-2 was produced in the same amounts by these different kinds of subjects. DNA from four clones lacking OKT4 established from four individuals of this family was sequenced. As reported elsewhere for different subjects, a single nucleotide substitution (CGG-->TGG) was found in all four cell lines. The mutation results in arginine being replaced by tryptophan. Analysis showed different hydrophobicity at positions 239 and 240 from the control, probably giving rise to a conformational change in CD4 accounting for lack of reactivity with the OKT4 monoclonal antibody. The incidence of homozygotes in the Japanese population was found to be 0.47% by examination of 1478 random samples, and on the basis of this value, the incidence of heterozygotes was estimated to be 12.8%.

Amino Acid Sequence↗
PubMed1992

Gene structure of human indoleamine 2,3-dioxygenase.

Two genomic DNA clones that encode human indoleamine 2,3-dioxygenase (IDO) were isolated from the human genomic DNA library using the IDO cDNA as a probe, and their restriction maps and partial nucleotide sequences were determined. The human IDO gene spanned 15 kilobase pairs with ten exons. The 5' terminus of the IDO mRNA was 33 nucleotides upstream of the translation initiation codon ATG. The 5' flanking region contained ISRE, X-box, and Y-box like sequences. Southern blot analysis of the human genomic DNA indicated that the human IDO gene was present in a single copy in the genome.

Alternative Splicing↗
PubMed1992

Localization of kynurenine aminotransferase immunoreactivity in the rat hippocampus.

The localization and distribution of kynurenine aminotransferase (KAT), the biosynthetic enzyme of the excitatory amino acid receptor antagonist, kynurenic acid, was studied in the rat hippocampal formation with immunohistochemical methods. The enzyme was found mainly in glial cells that could be distinguished as 3 types on the basis of their shapes and locations. Typically, these cells shared the morphological features of astrocytes and exhibited glial fibrillary acidic protein immunoreactivity as demonstrated by a double-labeling technique. The distribution of KAT-containing glial cells was heterogeneous throughout the hippocampal formation. In the hippocampus, the stratum lacunosum-moleculare of Ammon's horn and the hilus contained a higher density of KAT-positive glial cells than other regions, whereas the lowest density of KAT glial cells was observed in the granule cell layer of the dentate gyrus and in the stratum radiatum of CA subfields. In the subicular complex, the density of KAT-containing glial cells was generally higher in the superficial than in the deep layer. Hippocampal neurons exhibiting KAT immunoreactivity, distinguished as nonpyramidal cells, were very few in number and mainly distributed in strata oriens and pyramidale of Ammon's horn. Substantially more KAT-positive neurons were observed in layers II and III of the subicular complex. The organization of cellular elements containing KAT may be of relevance for the function and possible dysfunction of kynurenic acid in the rat hippocampal formation.

Animals↗
PubMed1992

Formation of hydroxanthommatin-derived radical in the oxidation of 3-hydroxykynurenine.

Using ESR, a radical (g = 2.004) was detected in the reaction mixture of 3-hydroxykynurenine (3-HKY), H2O2, and horseradish peroxidase. The radical was stable and was detected even after 5 h. On HPLC analysis of the reaction mixture, two radical peaks (Peak-1 and Peak-2) were detected using ESR. The ESR spectra of Peak-1 and Peak-2 radicals were the same and identical with that of the original radical in the reaction mixture. The retention times of Peak-1 and Peak-2 corresponded to those of authentic xanthommatin (XA) and hydroxanthommatin (Hydro-XA), respectively, XA being formed in the oxidation of 3-HKY by potassium ferricyanide and Hydro-XA being formed in the reduction of XA by sodium metabisulfite. The absorbance spectra of Peak-1 and Peak-2 were nearly identical with those of authentic XA and Hydro-XA. The absorbance spectrum of Peak-2 changed from that of Hydro-XA to that of XA, indicating that Hydro-XA auto-oxidized to XA in the air. The ESR signal intensity of the Peak-2 radical developed in accordance with the progress of this auto-oxidation of Hydro-XA to XA. It was supposed that the Peak-2 radical was generated in the auto-oxidation of Hydro-XA after its elution from the HPLC column. Thus, the radical seemed to be the one-electron oxidized form of Hydro-XA. The Peak-1 radical appeared to be the true retention of the radical on the column and to be eluted with a much larger amount of XA. The separation of the radical from XA was impossible on the column. Hemoglobin (Hb) or hematin also induced the same radical in the reaction mixture of 3-KHY, H2O2, and Hb or hematin.

Animals↗
PubMed1992

Oxidation of 3-hydroxykynurenine catalyzed by methemoglobin with hydrogen peroxide.

Methemoglobin (metHb) with H2O2 catalyzed the oxidation of 3-hydroxykynurenine (3-HKY) in the reaction mixture of metHb, 3-HKY, and H2O2. The spectrophotometric experiments suggest the following mechanism for the 3-HKY oxidation by metHb with H2O2. MetHb first reacts with H2O2 to form the ferryl complex of Hb. This species then oxidizes 3-HKY, while it returns to metHb. 3-HKY was more reactive with the ferryl complex than glutathione but less reactive than ascorbic acid. Scavengers of the hydroxyl radical, dimethyl sulfoxide and ethanol, scarcely inhibited the 3-HKY oxidation by metHb with H2O2. Desferrioxamine, a metal chelator, hardly suppressed the 3-HKY oxidation. These results indicate that the hydroxyl radical is not involved in the 3-HKY oxidation by metHb with H2O2.

Free Radicals↗
PubMed1992

In vivo 19F MR spectroscopic study of metabolism of 5-fluorotryptophan in rat liver.

The metabolism of 5-fluorotryptophan in rat liver was examined by in vivo 19F MR spectroscopy. After i.v. injection of 200 mg/kg b.w. of 5-fluorotryptophan the substance was noted immediately as a strong peak, which decreased gradually. Another peak appeared about 40 min after the injection. The chemical shift value of this peak was 1.6 ppm from that of 5-fluorotryptophan. Kynurenine is known to be a major metabolite of tryptophan in the liver. We synthesized 5-fluorokynurenine from 5-fluorotryptophan by ozonolysis. The chemical shift value of 5-fluorokynurenine was confirmed to be coincident with that of the metabolite peak. This strongly suggests that the metabolite peak of 5-fluorotryptophan observed in this study was the 5-fluorokyrurenine signal. We also applied this method for the CCl4-injured liver. In the liver injury group, the metabolite peak appeared slowly and the intensity was low compared to that of the normal group, though the peak of 5-fluorotryptophan decreased similarly as in the normal liver. These results suggest that the decrease of 5-fluorotryptophan is due mainly to the renal excretion, as the injured liver could not metabolize 5-fluorotryptophan.

Animals↗
PubMed1991

Kinetic properties of human liver tryptophan pyrrolase.

Human liver tryptophan pyrrolase (TPO) activity exhibited substrate level regulation. TPO showed biphasic activity to tryptophan when low ascorbate was used as an activator. The high affinity form (Km for tryptophan: 0.05 mM) was promoted by low ascorbate and low tryptophan. The low affinity form (Km for tryptophan: 0.4 mM) was induced by high concentrations of tryptophan or ascorbate. Both high and low affinity forms showed the same affinity to oxygen. The high affinity form was also induced by pyrroloquinoline quinone, but this effect was decreased by catalase, suggesting the participation of H2O2.

Ascorbic Acid↗
PubMed1991

In vitro effect of dimethoate on the activity of tryptophan pyrrolase in rat liver.

Total and holo-enzyme activities of tryptophan 2,3-dioxygenase were measured in vitro in the presence and absence of the organophosphorous insecticide, dimethoate. Addition of dimethoate to the reaction mixture decreased the activities of both total and holo-forms. Total and holo-enzyme activities were decreased by 34% and 26%, respectively, by 1 mM dimethoate. On the other hand, 5 mM dimethoate resulted in 56% and 34% inhibition to total and holo-enzyme activities, respectively. Lineweaver-Burk plot of the total-enzyme activity at different tryptophan concentration in the presence of 2 mM dimethoate gave uncompetitive type of inhibition.

Animals↗
PubMed1991

Superoxide dismutase enhances the toxicity of 3-hydroxyanthranilic acid to bacteria.

Cu,Zn.superoxide dismutase (SOD) enhanced the toxicity of 3-hydroxyanthranilic acid (3-HAT) to Salmonella typhimurium strain TA 102, evaluated as ability to form colonies. MnSOD showed the same effect. Inactivated Cu.ZnSOD had no effect. SODs accelerated the oxidation of 3-HAT, but inactivated Cu.ZnSOD caused little acceleration. It is proposed that the acceleration of 3-HAT oxidation leads to the enhancement of the 3-HAT toxicity. Catalase protected the bacteria from the toxicity of 3-HAT enhanced by Cu,ZnSOD, indicating that hydrogen peroxide generated in the oxidation of 3-HAT is involved in the toxicity. SODs accelerate the oxidation of 3-HAT and generate more hydrogen peroxide, that causes the enhancement of the 3-HAT toxicity to the bacteria. However, hydrogen peroxide alone was not so toxic. Hydrogen peroxide with 3-HAT was more toxic to the bacteria.

3-Hydroxyanthranilic Acid↗