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H Ichinose

Publications and source records attributed to H Ichinose.

At least 19 recordsLinked to original sources
PubMed1992

Tissue-specific alternative splicing of the first exon generates two types of mRNAs in human aromatic L-amino acid decarboxylase.

Aromatic-L-amino-acid decarboxylase (AADC) is an enzyme that plays an essential role in synthesizing catecholamines and serotonin in neuronal and endocrine tissues. AADC has also been detected in other nonneuronal tissues including liver and kidney, although its physiological role in nonneuronal tissues has not yet been defined. Previously we have cloned a human AADC cDNA from a neuronal tissue (pheochromocytoma) [Ichinose, H., Kurosawa, Y., Titani, K., Fujita, K., & Nagatsu, T. (1989) Biochem. Biophys. Res. Commun. 164, 1024-1030] and the corresponding genomic DNA [Sumi-Ichinose, C., Ichinose, H., Takahashi, E., Hori, T., & Nagatsu, T. (1992) Biochemistry 31, 2229-2238]. Here we present isolation and characterization of AADC cDNA and genomic DNA from a nonneuronal tissue (human liver). The nonneuronal and neuronal AADC mRNAs differed only in the region corresponding to the untranslated first exon. The first exon for the nonneuronal-type mRNA was located 4.2 kilobases upstream to that for the neuronal-type mRNA and 22 kilobases from exon 2, to which it is spliced. Determination of the transcription initiation site indicated that the length of the nonneuronal-type exon 1 was 200 bp. A TATA box-like motif was located between positions -26 and -20 from the transcription initiation site. These results showed that an alternative usage of the first exon in the 5'-untranslated regions produces two types of mRNAs in AADC and suggested that alternative splicing would regulate the tissue-specific expression of AADC.

Adrenal Glands↗
PubMed1992

Multiple mRNA forms of human GTP cyclohydrolase I.

To isolate full length cDNA clones encoding human GTP cyclohydrolase I, the first and rate-limiting enzyme in tetrahydrobiopterin biosynthesis, a cDNA library generated from human liver was screened by plaque hybridization. Analysis of the clones, hybridized with rat cDNA fragment, by restriction mapping and partial sequencing showed the existence of three kinds of cDNAs. All three cDNAs were identical in their central and 5' regions. They were, however, found to diverge at 3' ends. Furthermore, the three species of mRNAs corresponding to the three cDNAs were detected in human liver by reverse transcription-polymerase chain reaction (RT-PCR) analysis. These results indicate that, in humans, GTP cyclohydrolase I molecules are encoded by at least three distinct mRNAs.

Amino Acid Sequence↗
PubMed1992

Molecular cloning of genomic DNA and chromosomal assignment of the gene for human aromatic L-amino acid decarboxylase, the enzyme for catecholamine and serotonin biosynthesis.

Aromatic L-amino acid decarboxylase (AADC) catalyzes the decarboxylation of both L-3,4-dihydroxyphenylalanine and L-5-hydroxytryptophan to dopamine and serotonin, respectively, which are major mammalian neurotransmitters and hormones belonging to catecholamines and indoleamines. This report describes the organization of the human AADC gene. We proved that the gene of human AADC consists of 15 exons spanning more than 85 kilobases and exists as a single copy in the haploid genome. The boundaries between exon and intron followed the AG/GT rule. The sizes of exons and introns ranged from 20 to 400 bp and from 1.0 to 17.7 kb, respectively, while the sizes of four introns were not determined. Untranslated regions located in the 5' region of mRNA were encoded by two exons, exons 1 and 2. The transcriptional starting point was determined around G at position -111 by primer extension and S1 mapping. There were no typical "TATA box" and "CAAT box" within 540 bp from the transcriptional starting point. The human AADC gene was mapped to chromosome band 7p12.1-p12.3 by fluorescence in situ hybridization. This is the first report on the genomic structure and chromosomal localization of the AADC gene in mammals.

Amino Acid Sequence↗
PubMed1992

Comparison of characteristics of bovine aromatic L-amino acid decarboxylase with human enzyme.

Aromatic L-amino acid decarboxylase (AADC) was purified from bovine adrenal medulla and properties of this enzyme were compared with those of AADC from human pheochromocytoma. The molecular weights of the subunits were identical between human and bovine enzymes and estimated to be 50,000 by SDS-polyacrylamide gel electrophoresis. An isoelectric point of the human enzyme was 5.7, while the bovine enzyme showed several distinct bands at the region of pH 4.9-5.3 in the absence of urea. Multiplicity of the isoelectric point of bovine AADC disappeared in the presence of urea. These results showed that there were some differences between the properties of human and bovine AADC in spite of the high homology (88%) in their primary structures.

Adrenal Medulla↗
PubMed1991

Cloning and sequencing of cDNA encoding human sepiapterin reductase--an enzyme involved in tetrahydrobiopterin biosynthesis.

A full-length cDNA clone for sepiapterin reductase, an enzyme involved in tetrahydrobiopterin biosynthesis, was isolated from a human liver cDNA library by plaque hybridization. The nucleotide sequence of hSPR 8-25, which contained an entire coding region of the enzyme, was determined. The clone encoded a protein of 261 amino acids with a calculated molecular mass of 28,047 daltons. The predicted amino acid sequence of human sepiapterin reductase showed a 74% identity with the rat enzyme. We further found a striking homology between human SPR and carbonyl reductase, estradiol 17 beta-dehydrogenase, and 3 beta-hydroxy-5-ene steroid dehydrogenase, especially in their N-terminal region.

Alcohol Oxidoreductases↗
PubMed1991

Comparative studies on the structure of human tyrosine hydroxylase with those of the enzyme of various mammals.

1. Tyrosine hydroxylase (TH) is the first and rate-limiting enzyme in catecholamine biosynthesis. 2. The structures of TH from various species have been elucidated. 3. We have cloned and determined the sequences of four types of human TH cDNA and human TH genomic DNA. 4. We have compared the amino acid sequences of TH from various species. 5. The results indicate that the amino acid sequences of TH are highly conserved among various species, and that TH consists of the regulatory domain containing serine residues which are phosphorylated by protein kinases and of the catalytic domain where the substrates, tyrosine and oxygen, and the cofactor, tetrahydrobiopterin, are bound. 6. Comparison of amino acid sequences among TH from various species can give us useful information on the functional importance of each amino acid residue.

Amino Acid Sequence↗
PubMed1990

Multiple mRNAs of monkey tyrosine hydroxylase.

The multiplicity of tyrosine hydroxylase (TH) mRNA was examined in two species of primate, Macaca irus and Macaca fuscata, one species of insectivore, Sunkus murinus and one species of rodent, rat. To investigate the TH multiplicity, total RNAs from various species of animals were reverse transcribed and 5' portion of TH cDNAs were amplified by polymerase chain reaction. The resulted DNA fragments were analyzed by agarose gel electrophoresis. Two types of TH mRNA corresponding to type 1 and type 2 were detected in adrenal gland and brain of both species of primate. In contrast, only a single form of TH mRNA was detected in Sunkus murinus and rat.

Adrenal Glands↗
PubMed1990

The complete amino acid sequence of the mature form of rat sepiapterin reductase.

The partial amino acid sequence of rat sepiapterin reductase was determined using peptides generated by cleavage of the S-carboxyamidomethylated protein with Achromobacter protease I, cyanogen bromide, chymotrypsin or BNPS-skatole. The protein began with N-acetyl methionyl residue at the N-terminus and ended with isoleucyl residue at the C-terminus. The present results essentially coincided with the amino acid sequence predicted from the nucleotide sequence of the cDNA recently reported by Citron et al. (Proc. Natl. Acad. Sci. USA 87, 6436-6440 (1990)), clarified the processing event during the biosynthesis and provided the complete amino acid sequence of the mature form of the enzyme.

Alcohol Oxidoreductases↗
PubMed1990

Characterization of recombinant human aromatic L-amino acid decarboxylase expressed in COS cells.

The expression vector containing the full-length cDNA of human aromatic L-amino acid decarboxylase (EC 4.1.1.28) was transfected in COS cells by a modified calcium phosphate coprecipitation method. The cells transfected with plasmids that had a true direction of the cDNA gave a major immunoreactive band at 50 kDa. This expressed enzyme catalyzed the decarboxylation of L-3,4-dihydroxyphenylalanine (L-DOPA), L-5-hydroxytryptophan (L-5-HTP) and L-threo-3,4-dihydroxyphenylserine. The optimal pH of the enzyme activity with L-DOPA as a substrate was 6.5, whereas the enzyme had a broad pH optimum when L-5-HTP was used as a substrate. Addition of pyridoxal phosphate to the incubation mixture greatly enhanced the activity for both L-DOPA and L-5-HTP.

5-Hydroxytryptophan↗
PubMed1989

Isolation and characterization of a cDNA clone encoding human aromatic L-amino acid decarboxylase.

The nucleotide sequence of a cDNA clone that includes the entire coding region of human aromatic L-amino acid decarboxylase gene is presented. A human pheochromocytoma cDNA library was screened using an oligonucleotide probe which corresponded to a partial amino acid sequence of the enzyme purified from the human pheochromocytoma. The isolated cDNA clone encoded a protein of 480 amino acids with a calculated molecular mass of 53.9 kDa. The amino acid sequence Asn-Phe-Asn-Pro-His-Lys-Trp around a possible cofactor (pyridoxal phosphate) binding site is identical in human, Drosophila, and pig enzymes.

Adrenal Gland Neoplasms↗
PubMed1989

Uptake of heterocyclic amines, Trp-P-1 and Trp-P-2, into clonal rat pheochromocytoma PC12h cells by dopamine uptake system.

Heterocyclic amines, 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), are known to be produced in food by cooking and are carcinogenic. These amines were found to be accumulated in clonal rat pheochromocytoma PC12h cells and to reduce enzyme activity related to catecholamine synthesis. The mechanism of uptake of these heterocyclic amines into PC12h cells was studied. The uptake was dependent on the incubation time, the amount of the cells, and the concentrations of Trp-P-1 and Trp-P-2 in the incubation mixture. The uptake of these amines was saturable with their concentrations, and the uptake velocity followed the Michaelis-Menten equation, indicating that the uptake was mediated by a transporting protein. The uptake was inhibited by dopamine and serotonin, but not by noradrenaline. Involvement of the dopamine uptake system in uptake of the heterocyclic amines was further indicated by the fact that nomifensine and mazindol, specific inhibitors of dopamine uptake, reduced the uptake, but sulpiride, an antagonist of D2 receptor, did not. The significance of the uptake of the carcinogenic heterocyclic amines was discussed in relation to their possible neurotoxicity in the human brain.

Adrenal Gland Neoplasms↗
PubMed1989

High-resolution electron microscopy of ceramic interfaces.

Three observations described here were chosen not only to represent our recent interface studies in ceramics, but also to demonstrate how different the present status of interface research is with respect to the level of high-resolution electron microscopy. Certain common features may be found among the problems of ceramic interface studies. Importance of basal plane grain boundary, for example, is one of the characteristics of this type of heterogeneous compound. The crystalline heterogeneity has been ignored largely in the grain boundary structure study since it has been developed primarily for cubic metals. The new area of basic grain boundary interface structure study is opened now that description of this type of interface has become engineeringly important.

Aluminum↗
PubMed1989

[A study of bronchial sensitivity and bronchial reactivity using Astograph and transcutaneous oxygen tension in asthmatic children. The problems of simultaneous measurement].

Bronchial sensitivity and reactivity in 60 patients with bronchial asthma was measured using the Astograph and simultaneous transcutaneous oxygen tension [PtcO2]. In spite of increasing respiratory resistance, there were some cases in which PtcO2 did not show remarkable decrease. The PtcO2 percentage was defined as (basal value of PtcO2 - bottom value of PtcO2)/(basal value of PtcO2). The correlation between PtcO2% and the basal value of PtcO2 was relatively high (r = 0.42, n = 58, p less than 0.005). The correlation between PtcO2% and V50/Ht or V25/Ht was also relatively high (r = 0.41, n = 45, p less than 0.01, r = 0.49, n = 45, p less than 0.001, respectively). In some cases of small airway obstruction or low basal value of PtcO2, was smaller. The patients of over 70% in FEV1.0/VCP were in accord with that of over 70 mmHg in the basal value of PtcO2. The results suggest the recommended basal value of PtcO2 to measure bronchial sensitivity and reactivity may be over 70 mmHg.

Adolescent↗
PubMed1988

Reduction of aromatic L-amino acid decarboxylase activity in clonal pheochromocytoma PC12h cells by culture in the presence of N-methyl-4-phenylpyridinium ion (MPP+).

Rat clonal pheochromocytoma PC12h cells were cultured in the presence of N-methyl-4-phenylpyridinium ion (MPP+) and the activity of aromatic L-amino acid decarboxylase (AADC) was reduced after 3 and 6 days of culture. AADC activity in control cells was increased markedly by addition of pyridoxal 5-phosphate (PLP) to the reaction mixture, but that in the cells cultured in the presence of MPP+ was not increased by addition of PLP. After 6 days culture, AADC activity was almost negligible in the cells cultured in the presence of 1 mM MPP+, but PLP concentration in the cells was not reduced. AADC in the cells cultured in the presence of MPP+ reduced the affinity to PLP, but the affinity to a substrate, L-DOPA, did not change. Intracellular concentration of AADC protein was not reduced, as shown by an immunobinding assay with anti-AADC antibody. These data indicate that MPP+ may induce conformational changes in AADC protein and reduces its affinity to the cofactor, PLP.

1-Methyl-4-phenylpyridinium↗
PubMed1988

Reduction of enzyme activity of tyrosine hydroxylase and aromatic L-aminoacid decarboxylase in clonal pheochromocytoma PC12h cells by carcinogenic heterocyclic amines.

Out of carcinogenic heterocyclic amines, which are produced by pyrolysis of tryptophan in food, 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) were found to reduce the activity of enzymes related to catecholamine metabolism in clonal rat pheochromocytoma PC12h cells. By 6 days' culture in the presence of 10 nM to 10 microM Typ-P-1 and -2, these heterocyclic amines were accumulated in the cells, and activity of tyrosine hydroxylase (TH) and aromatic L-aminoacid decarboxylase (AADC) were reduced markedly. Reduction of these enzyme activity was observed with Trp-P-1 and -2 at the concentrations lower than 1 microM, while cell protein and enzyme activity of a non-specific enzyme, beta-galactosidase were reduced only with 10 microM Trp-P-1. These results show that these heterocyclic amines are neurotoxins specific for dopaminergic neurons.

Animals↗
PubMed1988

Effects of heterocyclic amines in food on dopamine metabolism in nigro-striatal dopaminergic neurons.

We investigated the effects of 14 heterocyclic amines in food on nigro-striatal dopaminergic neurons. Among 14 compounds tested, 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) caused substantial decreases in 3,4-dihydroxy-phenylalanine (DOPA) formation in striatal tissue slice system. When Trp-P-1 or Trp-P-2 was unilaterally infused in the rat striatum by an in vivo micro-dialysis technique, both compounds produced a transient increase of dopamine (DA) and continuous decreases in the metabolites, homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid (DOPAC) in the perfusate. This suggests that the two compounds inhibit monoamine oxidase (MAO) in vivo. Indeed they were found to be very potent inhibitors of MAO in vitro. Systemic administration of Trp-P-1 to C57 Black mice caused a marked decrease of DOPAC content and a significant increase of DA in the striatum, indicating inhibition of MAO in vivo. These results suggest that Trp-P-1 and Trp-P-2 contained in food could alter the metabolism of DA in the brain.

3,4-Dihydroxyphenylacetic Acid↗