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Biomedical subjects

S Shin

Publications and source records attributed to S Shin.

At least 163 records · Page 9Linked to original sources
PubMed1991

Plant thioredoxin h: an animal-like thioredoxin occurring in multiple cell compartments.

Thioredoxin h has been purified to electrophoretic homogeneity from spinach roots using a procedure devised for leaves. The root thioredoxin (h2 form) differed from chloroplast and animal thioredoxins in showing an atypical active site (Cys-Ala-Pro-Cys) but otherwise resembled animal thioredoxin in structure. Sequence data for a total of 72 residues of spinach root thioredoxin h2 (about 69% of the primary structure) showed 43-44% identity with rabbit and rat thioredoxin. Analysis of cell fractions from the endosperm of germinating castor beans revealed that thioredoxin h occurs in the cytosol, endoplasmic reticulum, and mitochondria. The present findings demonstrate a similarity between plant thioredoxin h and animal thioredoxins in structure and intracellular location and raise the question of whether these proteins have similar functions.

Amino Acid Sequence↗
PubMed1991

Molecular cloning and sequence analysis of cDNAs for five major subunits of human proteasomes (multi-catalytic proteinase complexes).

Proteasomes are multicatalytic proteinase complexes consisting of a set of non-identical polypeptide components. Of these multiple components, the nucleotide sequences of five major subunits (named HC2, HC3, HC5, HC8 and HC9) of human proteasomes have been determined from recombinant cDNA clones by screening a human HepG2 hepatoblastoma cell cDNA library with rat proteasome cDNAs isolated previously as probes. The polypeptides deduced from their nucleotide sequences consisted of 263, 234, 241, 255 and 261 amino acid residues with calculated molecular weights of 29,554, 25,897, 26,487, 28,431 and 29,482, respectively, which are encoded by single independent genes. The primary structures of these subunits of human proteasomes closely resemble those of their rat counterparts and show considerably high inter-subunit homology, although the homology of HC5 is relatively low. These findings, together with the structural similarities of other eukaryotic proteasomes including those of Drosophila and yeast (Saccharomyces cerevisiae) support and extend the previously proposed concept that eukaryotic proteasome genes form a multi-gene family with the same evolutionary origin.

Amino Acid Sequence↗
PubMed1991

Ethanol-acetylcholinesterase-inhibitor interactions: inhibitor hydrophobicity and site specificity dependence.

1. Depending on the hydrophobicity and the site specificity of an inhibitor, striking differences were found in ethanol-acetylcholinesterase (AChE)-inhibitor interactions. 2. AChE used was from electric eel and was purified by affinity chromatography. 3. Ethanol at 10-200 mM reduced the inhibitory ability of tetrabutylammonium bromide (Bu4NBr). 4. The observed reduction might be a result of Bu4NBr inhibition being partially compensated for by an ethanol activation effect. 5. In contrast to Bu4NBr, propidium and edrophonium are not involved in hydrophobic interaction with AChE. 6. Their abilities to inhibit AChE activity were enhanced by ethanol. 7. Such an enhancement could not result from combining individual perturbations from ethanol and propidium or edrophonium, since ethanol itself increased the AChE activity. 8. In the presence of ethanol, propidium which binds to the peripheral site of the enzyme remained as an uncompetitive inhibitor, while edrophonium which binds to the active site was changed from a competitive inhibitor to a mixed one. 9. The effect of ethanol was therefore greater in the inhibitor which is involved with the active-site binding. 10. Fluorescence quenching studies of propidium-bound enzyme and edrophonium-bound enzyme revealed that ethanol in the concentration less than or equal to 400 mM did not cause significant conformational change at both the peripheral and the active sites of the enzyme.

Acetylcholinesterase↗
PubMed1991

Biochemical studies of the actions of ethanol on acetylcholinesterase activity: ethanol-enzyme-solvent interaction.

1. Biochemical studies of the actions of ethanol on the activity of acetylcholinesterase (AChE), isolated from electric eel (Electrophorus electricus) and purified by affinity chromatography, were performed to elucidate ethanol-enzyme-solvent interactions. 2. Ethanol at a low concentration [( EtOH] = 2.7-200 mM) was found to enhance AChE activity slightly and systematically. 3. This observation was consistent with the result from enzyme-kinetic studies that ethanol might noncompetitively activate AChE activity at this lower concentration range. 4. If ethanol alters the hydrophobic site interaction on the enzyme and subsequently induces a favorable conformation for the active center of the enzyme, then a slight increase in the AChE activity in the presence of a low concentration of ethanol will be observed. 5. This speculation was supported by the finding of ethanol's ability to perturb the inhibition of AChE activity by tetrabutylammonium bromide and to affect hydrophobic interaction between this salt and AChE, as investigated by enzyme activity and microcalorimetric measurements. 6. The ethanol effect on the activity of this soluble AChE was found to be distinguishable from that on a membrane-bound AChE. 7. Furthermore, to elucidate the effect of ethanol-solvent interaction on AChE activity, enzyme activity in the presence of much higher concentrations of ethanol was also examined. 8. At [EtOH] greater than 800 mM, ethanol can perturb the structure of water around hydrophobic areas of AChE, causing an instability in the enzyme conformation and subsequently decreasing AChE activity.

Acetylcholinesterase↗
PubMed1991

[A case of acquired cystic disease of bilateral kidneys with renal cell carcinoma following long-term hemodialysis].

We report a case of bilateral renal cell carcinoma which developed during about 14 years of hemodialysis. The patient of male was a 39-year-old with a chief complaint of macrohematuria 14 years prior to dialysis therapy. Computed tomography revealed multiple cystic changes of bilateral kidneys and a high density area in the right kidney. He was admitted to our department in April 1988. He was suspected of renal cell carcinoma of the right kidney and underwent transperitoneal radical nephrectomy on the right kidney. The left kidney was also resected simultaneously in part because it failed to function and in part because the long-term hemodialyzed patients are considered to have a complication of renal cell carcinoma at a high frequency. Pathological diagnosis was bilateral acquired cystic disease of the kidney (ACDK) with renal cell carcinoma. The kidney develops multiple cystic changes following long-term hemodialysis, which forms a high risk for development of renal cell carcinoma. This is a case of bilateral renal cell carcinoma which occurred after long-term hemodialysis, was reported with discussion and reference to the literature.

Adult↗
PubMed1991

Novel method for quantifying alpha(1----3)-L-fucosyltransferase activity in serum.

A novel method has been developed to quantify alpha(1----3)-L-fucosyltransferase activity in human sera by applying a sandwich-type immunoradiometric assay. H type 2 trisaccharide (6Fuc alpha 1----2Gal beta 1----4GlcNAc) covalently attached to bovine serum albumin (BSA) was used as an acceptor and incubated with serum samples in the presence of guanosine diphosphate-fucose. The resulting product, Y tetrasaccharide (Fuc alpha 1----2Gal beta 1----4[Fuc alpha 1----3] GlcNAc beta-BSA), was detected by a sequential use of anti-BSA antibody-coated bead and 125I-labeled anti-Y antibody. Inter- and intra-assay CVs for alpha(1----3)-L-fucosyltransferase were both less than 4%, and the results of the dilution linearity and analytical recovery studies were satisfactory. Using the present assay method, we measured alpha(1----3)-L-fucosyltransferase in serum from patients with benign and malignant gastric disorders and in healthy subjects. The detection rate of alpha(1----3)-L-fucosyltransferase for cancer was apparently higher than that of carcinoembryonic antigen measured in the same samples, particularly in the early clinical stage; indeed, no correlation was observed between the concentrations of the two potential markers. The results indicate that the present assay method seems to be excellent for the determination of serum alpha(1----3)-L-fucosyltransferase activity and useful for the detection of cancer-associated increases of the enzyme activity at the early stage of gastric cancer.

Carbohydrate Sequence↗
PubMed1990

[Relationship between human papillomavirus and oncogenes (c-myc, N-myc) amplification in human cervical cancers].

The human papillomavirus detection and oncogenes amplifications were studied on DNAs from fifteen cervical cancers. We detected HPV16 and HPV18 using Southern blot hybridization and polymerase chain reaction (PCR) technique. The positive subjects of HPVs were eight cases (53%) observed by Southern blot hybridization and fourteen cases (93%) by PCR technique. The gene amplifications of oncogenes (c-myc and N-myc) were analysed by slot-blot method and were observed in c-myc but not in N-myc. The "LARGE" gene amplification (more than five fold) in c-myc was observed in one case (7%) and the "SMALL" gene amplifications (less than five fold) were observed in six cases (40%) in human cervical cancers. Although one of five cases (20%) with HPV16 was present c-myc gene amplification, all of three cases (100%) with HPV18 were found c-myc gene amplifications. In two out of three cases obtained more than three fold c-myc gene amplifications, HPV were not detectable. It is suggested that the negative correlation between gene amplification and numbers of HPV copies exist in advanced cervical cancers.

Adult↗
PubMed1990

Novel forms of ferredoxin and ferredoxin-NADP reductase from spinach roots.

Ferredoxin and the enzyme catalyzing its reduction by NADPH, ferredoxin-NADP reductase (ferredoxin-NADP+ oxidoreductase or FNR), were found to be present in roots of spinach (Spinacia oleracea). Localization experiments with endosperm of germinating castor beans (Ricinus communis), a classical nonphotosynthetic tissue for cell fractionation studies, confirmed that ferredoxin and FNR are localized in the plastid fraction. Both proteins were purified from spinach roots and found to resemble their leaf counterparts in activity, spectral properties, and complex formation, but to differ in amino acid composition and amino terminal sequence. The results indicate that the primary structures of the FNR and ferredoxin of spinach roots differ from that of the corresponding leaf proteins. Together with earlier findings, the present results provide evidence that nonphotosynthetic plastids, including those of roots, are capable of reducing ferredoxin with heterotrophically generated NADPH.

Amino Acid Sequence↗
PubMed1990

Proteasomes are essential for yeast proliferation. cDNA cloning and gene disruption of two major subunits.

The cDNAs encoding two major subunits, named YC1 and YC7-alpha, of yeast proteasomes (multicatalytic proteinase complexes) were isolated and sequenced. As deduced from their nucleotide sequences, YC1 and YC7-alpha consist of 288 and 252 amino acid residues with calculated molecular weights of 31,534 and 27,999, respectively. They showed marked sequence homology to other eukaryotic proteasome components, suggesting that proteasomes are composed of a family of subunits with the same evolutional origin. To obtain information on the physiological role of proteasomes, we disrupted the chromosomal genes of YC1 and YC7-alpha of yeast cells independently, using isolated cDNA clones. Disruption of the coding region of one copy of the YC1 gene in diploid yeast created a recessive lethal mutation, but disruption of the 3'-noncoding region of the gene had no effect on cell proliferation. Disruption of the YC7-alpha gene also had a lethal effect on haploid yeast cells. These findings demonstrated that YC1 and YC7-alpha are both encoded by a single copy gene and that these genes are essential for proliferation of yeast cells.

Amino Acid Sequence↗
PubMed1990

Biological and immunological properties of human hepatocyte growth factor from plasma of patients with fulminant hepatic failure.

We have recently purified human hepatocyte growth factor (hHGF), a heterodimer with molecular weight of about 83,000, from plasma of patients with fulminant hepatic failure (Gohda, E. et al., J. Clin. Invest. 81, 414-419, 1988). Biological and immunological properties of hHGF were examined. Out of the well-known growth factors tested, only epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) stimulated DNA synthesis of adult rat hepatocytes in primary culture. hHGF enhanced the DNA synthesis at less than one-tenth of the molar concentrations of EGF and TGF-alpha. Half-maximal stimulations by hHGF, EGF and TGF-alpha were observed at 30, 400 and 900 pM, respectively. Maximal stimulation by TGF-alpha, however, was greater than those caused by hHGF and EGF. The effect of hHGF was additive with the maximal effects of EGF and TGF-alpha. Anti-hHGF antiserum was prepared in a rabbit by injecting with purified hHGF. This antiserum recognized nonreduced hHGF, but not reduced hHGF. The antiserum for hHGF did not inhibit growth-promoting activity of EGF, that was neutralized by incubation with anti-EGF antiserum. The activity of hHGF was completely inhibited by anti-hHGF antiserum, but not by anti-EGF antiserum. hHGF did not show any cross-reactivity to anti-EGF antiserum as measured by enzyme immunoassay for EGF. Thus, biological and immunological properties of hHGF are different from those of EGF and TGF-alpha.

Animals↗
PubMed1990

Molecular cloning of cDNA for proteasomes from rat liver: primary structure of component C3 with a possible tyrosine phosphorylation site.

Proteasomes are multicatalytic proteinase complexes consisting of multiple components. Previously, we reported the cloning and sequencing of cDNA for the largest component, C2, of rat liver proteasomes [Fujiwara, T., Tanaka, K., Kumatori, A., Shin, S., Yoshimura, T., Ichihara, A., Tokunaga, F., Aruga, R., Iwanaga, S., Kakizuka, A., & Nakanishi, S. (1989) Biochemistry 28, 7332-7340]. In the present study, the nucleotide sequence of another component (C3) of proteasomes has been determined from a recombinant cDNA clone isolated by screening a rat liver cDNA library with synthetic oligodeoxynucleotide probes corresponding to partial amino acid sequences of the protein. The deduced sequence of component C3 consists of 234 amino acid residues with a calculated molecular weight of 25,925. These values are consistent with those obtained by protein chemical analyses. A single mRNA species hybridizing to the C3 cDNA of rat liver was expressed in all rat tissues examined and in a variety of other eukaryotic organisms, its distribution being similar to that of C2 mRNA. The wide distribution of the gene product, possibly C3, suggests that this protein functions similarly in most eukaryotes. C3 is an unmodified protein of a single gene and differs from any other known protein, but its overall amino acid sequence resembles those of other proteasomal components, including C2, suggesting that these components belong to a single family of proteins with the same evolutionary origin.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1990

Antibody production and tissue irritation in swine vaccinated with Actinobacillus bacterins containing various adjuvants.

The effects that Actinobacillus pleuropneumoniae bacterins containing paraffin (mineral) oil, Al(OH)3, or lecithin-base oil adjuvants had on antibody production and muscle irritation were studied. Four hundred and thirty-two pigs were vaccinated twice (864 injection sites) at a 30-day interval. To assess effects of skin surface contamination on tissue reaction, 247 of the injections were made through skin soiled with manure. Serum samples for antibody determination and tissue samples were obtained at slaughter (15 to 90 days after vaccination). Bacterins containing Al(OH)3 or 5% lecithin-base oil as an adjuvant resulted in minimal tissue irritation. Bacterins containing paraffin oil or greater than 20% lecithin-base oil were more irritating to muscle, often resulting in a granuloma or an abscess at the injection site. Pigs given bacterins containing Al(OH)3 adjuvant had lower antibody titers than did pigs given bacterins containing paraffin oil or lecithin-base oil adjuvants.

Actinobacillus↗
PubMed1990

Monoclonal antibody to 2-amino-3-methylimidazo(4,5-f)quinoline, a dietary carcinogen.

In order to investigate relationships between human carcinogenesis and dietary carcinogens, one hybridoma cell line secreting a monoclonal antibody against 2-amino-3-methylimidazo(4,5-f)quinoline (IQ), a dietary carcinogen, was produced by fusing splenocytes from Balb/c mice immunized with IQ-Lysine(Lys)-Ascaris protein conjugate. The subclass of monoclonal anti-IQ antibody was determined by double immunodiffusion using culture medium and identified as IgG1. Monoclonal anti-IQ antibody was purified from ascites fluids of Balb/c mice with affinity chromatography on Protein A-Sepharose CL4B and analyzed concerning its cross-reactivity and sensitivity with RIA. Finally, we showed that our monoclonal antibody recognized IQ, 2-amino-3,4-dimethylimidazo(4,5-f)quinoline (MeIQ) and several beta-carbolines more intensely and that the sensitivity to IQ was 23 nmol in 50% displacement.

Animals↗