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T Yoshimura

Publications and source records attributed to T Yoshimura.

At least 181 records · Page 10Linked to original sources
PubMed1999

[A case of Sweet's syndrome (acute febrile neutrophilic dermatosis) showing transient jargon aphasia].

A 54-year-old woman visited our emergency service complaining of a severe language disturbance. She was fluently speaking something but most of the words were merely meaningless syllables. This jargon state lasted only four hours, then her abnormal speech rapidly and completely recovered within 24 hours. She had also suffered from painful oral ulcers, fever and erythema-like eruptions on her face for about three weeks. Skin biopsy of a facial lesion revealed a dense infiltrate of neutrophils in the dermis and minimal features of vasculitis, which, with other typical clinical findings, led us to the diagnosis of Sweet's syndrome. Although head CT scans, MRIs, MRA or SPECT could not detect any brain lesions, a cerebrospinal fluid examination showed a mild pleocytosis of 38/mm3 with 47% polymorphonuclear cells. There have been a few case reports on Sweet's syndrome accompanying neurologic symptoms, most of which are mild meningitis. We speculate that the transient aphasia was due to a focal lesion in the central nervous system attributable to Sweet's syndrome. Sweet's syndrome might bring inflammatory or ischemic lesions to the cerebrum as Behçet's disease.

Acute Disease↗
PubMed1998

Transamination as a side-reaction catalyzed by alanine racemase of Bacillus stearothermophilus.

The pyridoxal form of alanine racemase of Bacillus stearothermophilus was converted to the pyridoxamine form by incubation with its natural substrate, D- or L-alanine, under acidic conditions: the enzyme loses its racemase activity concomitantly. The pyridoxamine form of the enzyme returned to the pyridoxal form by incubation with pyruvate at alkaline pH. Thus, alanine racemase catalyzes transamination as a side function. In fact, the apo-form of the enzyme abstracted tritium from [4'-3H]pyridoxamine in the presence of pyruvate. A mutant enzyme containing alanine substituted for Lys39, whose epsilon-amino group forms a Schiff base with the C4' aldehyde of pyridoxal 5'-phosphate in the wild-type enzyme, was inactive as a catalyst for racemization as well as transamination. However, when methylamine was added to the mutant enzyme, it became active in both reactions. These results suggest that the epsilon-amino group of Lys39 participates in both racemization and transamination when catalyzed by the wild-type enzyme.

Alanine Racemase↗
PubMed1998

Hsc62, a new DnaK homologue of Escherichia coli.

We have cloned and expressed the ORF o170#1 of Escherichia coli, which encodes a 62-kDa protein sharing 33% homology in primary structure with DnaK and Hsc66, Hsp70 homologues of E. coli. The purified gene product, which we named Hsc62, clearly showed ATPase activity and was bound to a gelatin-agarose gel, from which it was specifically eluted with ATP magnesium salt. Thus, Hsc62 is similar to DnaK in this respect and probably functions as a molecular chaperon in E. coli. However, Hsc62 differs markedly from DnaK and also from Hsc66 in response to temperature: the optimum temperature for ATPase activity was increased stepwise in the order of Hsc62, Hsc66, and DnaK. Hsc66 is activated by DnaJ of E. coli in the same manner as DnaK, the natural partner protein of DnaJ. However, Hsc62 is distinct from the others: the ATPase activity of Hsc62 was not elevated by DnaJ.

Adenosine Triphosphatases↗
PubMed1998

Diastereoselective two-directional synthesis and cation transport ability of the central tristetrahydrofuranyl unit of meso polyether glabrescol as naturally occurring podand.

The diastereoselective synthesis of the central 2,5-linked tristetrahydrofuran (trisTHF) 6 of naturally occurring meso polyether, glabrescol (5), has been achieved in a two-directional manner by the vanadium(V)-catalyzed anti oxidative cyclizations of diol 14. The trisTHF podand 6 and its stereoisomeric analogs 7 and 8 exhibited outstanding cation transport abilities for physiologically important Na+ and K+.

Antineoplastic Agents, Phytogenic↗
PubMed1998

Positive regulation of the human macrophage stimulating protein gene transcription. Identification of a new hepatocyte nuclear factor-4 (HNF-4) binding element and evidence that indicates direct association between NF-Y and HNF-4.

We previously reported that the transcription of the human macrophage stimulating protein (MSP) gene was positively regulated by the binding of NF-Y to the CAATT sequence in the promoter region of this gene. Here we confirmed our previous results and further characterized the MSP promoter. Luciferase assay with deletion constructs showed the importance of the region, +32 to +39, for the promoter activity in Hep3B cells. Two nuclear protein-DNA probe (+15 to +40) complexes, C1 and C2, were detected by electrophoretic mobility shift assay. C2 was specific to hepatoma cells and contained hepatocyte nuclear factor-4 (HNF-4). DNase I footprinting with recombinant HNF-4 located another HNF-4-binding site in the distal region, -89 to -54. Mutations in the CAATT or the proximal HNF-4-binding site significantly reduced the promoter activity in Hep3B cells and HNF-4-transfected HeLa cells, whereas mutations in the distal HNF-4-binding site had no effect. The close proximity between the CAATT and the proximal HNF-4-binding site suggested that a direct contact between NF-Y and HNF-4 might be important. Protein-protein interaction between the A-subunit of NF-Y and HNF-4 was detected by a yeast two-hybrid system. The binding of in vitro translated HNF-4 to immobilized NF-YA and in vitro translated NF-YA to immobilized HNF-4 was also detected. These results suggest the binding of HNF-4 to the proximal HNF-4-binding site directs the basal transcription of the MSP gene, and the maximal promoter activity may depend on the direct association between HNF-4 and NF-Y.

Base Sequence↗
PubMed1998

Nucleotide sequence of Bombyx mori cytoplasmic polyhedrosis virus segment 8.

The segments 8 (S8) of the 10 double-stranded RNA genomes from Bombyx mori cytoplasmic polyhedrosis virus (BmCPV) strains I and H were converted into cDNAs, amplified by PCR, and cloned. The nucleotide sequence analysis of the two full-length S8 cDNAs showed that the segments consist of 1328 nucleotides encoding putative proteins (p44) of 390 amino acids with molecular masses of about 44 kDa, which have glutamic acid-rich and proline-rich domains in their central regions. They had quite high identity with each other: about 98% in nucleotide and amino acid sequences. The recombinant p44 expressed in BmN4 cells using the baculovirus vector was detected by immunoblot analysis. p44 was also confirmed with the same antiserum to be present in BmCPV-infected midgut cells, but not in polyhedra, virus virions and uninfected midgut cells, indicating that p44 is expressed as a nonstructural protein of BmCPV.

Amino Acid Sequence↗
PubMed1998

Plasmin can reduce the function of human beta2 glycoprotein I by cleaving domain V into a nicked form.

beta2-Glycoprotein I (beta2GPI) is a highly glycosylated plasma protein with the ability to bind negatively charged substances such as DNA, heparin, dextran sulfate, and negatively charged phospholipids. The most relevant physiological role of beta2GPI is supposed to be the regulation of the function of anionic phospholipids like cardiolipin (CL). beta2GPI consists of a single polypeptide chain (326 amino acid residues) with a molecular mass of about 50 kD and with five tandem repeated domains (I, II, III, IV, and V). In the previous study, we found that factor Xa can produce the nicked form by cleaving Lys 317-Thr 318, using recombinant human domain V (r-Domain V). However, the reaction was extremely slow. In the present paper, we found that plasmin can produce the nicked form of domain V, using recombinant domain V (r-Domain V) and beta2GPI from human plasma. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, r-Domain V was rapidly cleaved into a nicked form by plasmin, very slowly by factor Xa, but not by thrombin, tissue-type plasminogen activator, urokinase, and tissue factor/factor VIIa. The cleavage site of r-Domain V and beta2GPI by plasmin was proved to be Lys 317-Thr 318 by amino acid sequence analysis of the digest and of the C-terminal peptide isolated by high-performance liquid chromatography. The cleavage was completely inhibited by plasmin inhibitor (alpha2PI). The nicked form was demonstrated to show reduced affinity for CL with a dissociation constant of one order of magnitude larger than that of the intact beta2GPI. To determine whether the specific cleavage of beta2GPI by plasmin can occur also in plasma, human plasma was first acid-treated to inactivate alpha2PI and then incubated with urokinase. About 12% of beta2GPI in plasma was nicked when alpha2PI activity decreased to 80%. The nicked form was not generated in plasminogen-depleted plasma. These results suggest that plasmin can produce the nicked form of beta2GPI with the reduced ability to bind phospholipids in vivo.

Amino Acid Sequence↗
PubMed1998

Occurrence of pyridoxal 5'-phosphate-dependent serine racemase in silkworm, Bombyx mori.

D-Serine is known to occur in the silkworm Bombyx mori as well as in the mammalian central nervous systems. We found that serine racemase occurs in the insect, catalyzing the conversion of L-serine to its antipode. The enzyme was partially purified from pupae of the insect, and was inactivated by treatment with hydroxylamine and reactivated with pyridoxal 5'-phosphate (PLP). L-Alanine was racemized slowly by the enzyme at a rate of only about 6% of that of L-serine, and L-arginine and L-glutamine were inert as substrates. Therefore, the enzyme is a member of PLP-dependent amino acid racemases, and is distinct from alanine racemase (EC 5.1.1.1) and amino acid racemase with low substrate specificity (EC 5.1.1.10). This is the first report of the occurrence of serine racemase in eukaryotes producing D-serine.

Animals↗
PubMed1998

Peptidyl human heart chymase inhibitors. 2. Discovery of highly selective difluoromethylene ketone derivatives with Glu at P3 site.

Appropriate structural modification of the difluoromethylene ketone derivatives at both P3 and P' positions led us to the discovery of peptidyl human heart chymase inhibitor 12h which shows potent activity with Ki = 6 nM and high selectivity against closely related serine protease bovine alpha-chymotrypsin (chymotrypsin Ki = > 100 microM). Using the compound 12b, a docking study with human heart chymase was carried out to presume probable interactions.

Animals↗
PubMed1998

HTLV-I-associated myelopathy associated with multi-organ inflammatory disease: a case report.

We report a 73-year-old man with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM) complicated with multi-organ inflammatory disease, including Sjögren's syndrome, interstitial cystitis, and uveitis. The presence of HTLV-I proviral DNA in peripheral blood mononuclear cells (PBMC), cerebrospinal fluid, salivary gland, mucosa of urinary bladder, and aqueous humor was confirmed by polymerase chain reaction using HTLV-I pX region primer. Western blot analysis revealed the presence of anti-HTLV-I antibodies in serum, CSF, saliva, and urine, suggesting replication of HTLV-I in each tissue. A high load of HTLV-I proviral DNA (20 copies out of 100 PBMC) was present, associated with increased spontaneous proliferation of peripheral blood lymphocytes (24,747 cpm). Our results suggest that the high load of HTLV-I in patients with HAM may potentially induce systemic inflammation in several organs.

Aged↗
PubMed1998

Substrate inhibition of D-amino acid transaminase and protection by salts and by reduced nicotinamide adenine dinucleotide: isolation and initial characterization of a pyridoxo intermediate related to inactivation.

D-Amino acid transaminase, a pyridoxal phosphate (PLP) enzyme, is inactivated by its natural substrate, D-alanine, concomitant with its alpha-decarboxylation [Martinez del Pozo, A., Yoshimura, T., Bhatia, M. B., Futaki, S., Manning, J. M., Ringe, D., and Soda, K. (1992) Biochemistry 31, 6018-6023; Bhatia, M. B., Martinez del Pozo, A., Ringe, D., Yoshimura, T., Soda, K., and Manning, J. M. (1993) J. Biol. Chem. 268, 17687-17694]. beta-Decarboxylation of d-aspartate to d-alanine leads also to this inactivation [Jones, W. M., van Ophem, P. W., Pospischil, M. A., Ringe, D., Petsko, G., Soda, K., and Manning, J. M. (1996) Protein Sci. 5, 2545-2551]. Using a high-performance liquid chromatography-based method for the determination of pyridoxo cofactors, we detected a new intermediate closely related to the inactivation by d-alanine; its formation occurred at the same rate as the inactivation and upon reactivation it reverted to PLP. Conditions were found under which it was characterized by ultraviolet-visible spectral analysis and mass spectroscopy; it is a pyridoxamine phosphate-like compound with a C2 fragment derived from the substrate attached to the C'-4 of the pyridinium ring and it has a molecular mass of 306 consistent with this structure. In the presence of d-serine, slow accumulation of a quinonoid intermediate is also related to inactivation. The inactivation can be prevented by salts, which possibly stabilize the protonated aldimine coenzyme complex. The reduced cofactor, nicotinamide adenine dinucleotide, prevents D-aspartate-induced inactivation. Both of these events also are related to formation of the novel intermediate.

Alanine↗
PubMed1998

Isolation and characterization of a bovine neural specific protein (CRMP-2) cDNA homologous to unc-33, a C. elegans gene implicated in axonal outgrowth and guidance.

We have cloned the cDNA encoding bovine CRMP-2 from bovine brains. A full length cDNA encoding bovine CRMP-2 was isolated and sequenced. The deduced amino acid sequence reveals that the gene encodes a protein of 572 amino acids and is highly homologous to Caenorhabditis elegans unc-33, which controls the guidance and outgrowth of neuronal axons. The CRMP-2 transcript was present in bovine brains but not non-neural tissues, and its protein product existed in both soluble and membrane-bound forms. The expression of CRMP-2 protein and mRNA was upregulated during neuronal differentiation of rat PC12 cells. Immunoprecipitation of PC12 cell extracts shows that CRMP-2 was co-immunoprecipitated with a 190 kDa protein (p190). Both CRMP-2 and p190 were phosphorylated on serine residues in vivo and in vitro in a kinase assay of CRMP-2 immune complexes. Immunocytochemistry shows that CRMP-2 was exclusively localized in both the central and peripheral nervous systems in mouse embryos and detectable in the adult brain although the level of CRMP-2 decreased. The protein was expressed in the axon, dendrite, and cytoplasm of postmitotic neurons and in the cytoplasm of oligodendrocytes and astrocytes. The CRMP-2 gene maps to the region of mouse chromosome 14 syntenic with human chromosome 8p21. Taken together, these data suggest multi-functional roles for CRMP-2 in developing and adult nervous systems, and the biological activity of CRMP-2 could be regulated by phosphorylation reaction.

Amino Acid Sequence↗
PubMed1998

Identification of histidine 45 as the axial heme iron ligand of heme oxygenase-2.

A truncated, soluble, and enzymatically active form of human heme oxygenase-2 (DeltaHHO2) was expressed in Escherichia coli. To identify the axial heme ligand of HO-2, His-45 to Ala (DeltaH45A) and His-152 to Ala (DeltaH152A) mutants have been prepared using this expression system. DeltaH45A could form a 1:1 complex with hemin but was completely devoid of the heme degradation activity. A 5-coordinate-type ferrous NO EPR spectrum was observed for the heme-DeltaH45A complex. The DeltaH152A mutant was expressed as an inclusion body and was recovered from the lysis pellet by dissolution in urea followed by dialysis. The solubilized fraction obtained, however, was composed of a mixture of a functional enzyme and an inactive fraction. The inactive fraction was removed by Sephadex G-75 column chromatography since it eluted out of the column at the void volume. The gel filtration-purified DeltaH152A exhibited spectroscopic and enzymatic properties identical to those of wild-type. We conclude, in contrast to the previous reports (McCoubrey and Maines (1993) Arch. Biochem. Biophys. 302, 402-408; McCoubrey, W. K., Jr., Huang, T. J., and Maines, M. (1997) J. Biol. Chem. 272, 12568-12574), that His-45, but not His-152, in heme oxygenase isoform-2 is the proximal ligand of the heme and is essential for the heme degradation activity of the enzyme. His-152 appears to play a structural role in stabilization of the heme oxygenase protein.

Electron Spin Resonance Spectroscopy↗
PubMed1998

Nonstereospecific transamination catalyzed by pyridoxal phosphate-dependent amino acid racemases of broad substrate specificity.

Pyridoxal 5'-phosphate-dependent amino acid racemases of broad substrate specificity catalyze transamination as a side reaction. We studied the stereospecificities for hydrogen abstraction from C-4' of the bound pyridoxamine 5'-phosphate during transamination from pyridoxamine 5'-phosphate to pyruvate catalyzed by three amino acid racemases of broad substrate specificity. When the enzymes were incubated with (4'S)- or (4'R)-[4'-3H]pyridoxamine 5'-phosphate in the presence of pyruvate, tritium was released into the solvent from both pyridoxamine 5'-phosphates. Thus, these enzymes abstract a hydrogen nonstereospecifically from C-4' of the coenzyme in contrast to the other pyridoxal 5'-phosphate-dependent enzymes so far studied, which catalyze the stereospecific hydrogen removal. Amino acid racemase of broad substrate specificity from Pseudomonas putida produced D- and L-glutamate from alpha-ketoglutarate through the transamination with L-ornithine. Because glutamate does not serve as a substrate for racemization, the enzyme catalyzed the nonstereospecific overall transamination between L-ornithine and alpha-ketoglutarate. The cleavage and formation of the C-H bond at C-4' of the coenzyme and C-2 of the substrate thus occurs nonstereospecifically on both sides of the plane of the coenzyme-substrate complex intermediate. Amino acid racemase of broad substrate specificity is the first example of a pyridoxal enzyme catalyzing nonstereospecific transamination.

Amino Acid Isomerases↗
PubMed1998

Mutations of connexin32 in Charcot-Marie-Tooth disease type X interfere with cell-to-cell communication but not cell proliferation and myelin-specific gene expression.

Connexin32 (Cx32) is a gap junction protein and its mutations are responsible for X-linked Charcot-Marie-Tooth disease. We examined the functional abnormality of C6 glioma cells transfected with mutant (C53S and P172R) Cx32 genes. Nontransfected C6 did not express Cx32. Northern and Western blot analyses showed Cx32 mRNA and protein in cells with the wild-type gene as well as with the mutant Cx32 genes. An immunocytochemical study of cells with the wild-type gene showed the immunoreactive spots in the cell membrane. In cells with C53S or P172R mutant gene, however, the immunoreactivity was found in the cytoplasm. The scrape-loading method produced effective dye transfer in cells with the wild-type gene but not in those with mutant genes. A cell proliferation assay showed no differences in nontransfected cells, cells with the wild-type gene and those with the mutant genes. Messenger RNA expression for proteolipid protein did not change. These findings suggest that Cx32 gene mutation results in loss of cell-to-cell communication because of failure to incorporate Cx32 protein in the cell membrane. The mutations do not, however, interfere with cell proliferation or myelin-specific gene expression, at least myelin proteolipid protein expression in C6 glioma cells.

Blotting, Northern↗