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I S Choe

Publications and source records attributed to I S Choe.

34 records · Page 2Linked to original sources
PubMed1997

Complete sequence of the UPP gene encoding uracil phosphoribosyltransferase from Mycobacterium bovis BCG.

The nucleotide sequence of a 799 bp fragment of Mycobacterium bovis BCG containing the putative upp gene that encodes a uracil phosphoribosyltransferase (UPRTase [EC 2.4.2.9]) has been determined. The upp gene of BCG has an open reading frame (ORF) of 621 bp (207 amino acids) starting with GTG (position 112) and ending with TGA (position 733), and its molecular mass was calculated to be 21,864 Da. Comparative analyses of the deduced amino acid sequence of BCG UPRTase with the UPRTase of six bacterial genera revealed that 24% (50/211) of the residues are perfectly conserved and 32% (67/211) of the residues are well conserved.

Amino Acid Sequence↗
PubMed1997

Cloning and sequencing of the secY gene homolog from Mycobacterium bovis BCG.

The complete nucleotide sequence of a 1,513 bp fragment of Mycobacterium bovis BCG containing the secY gene homolog and partial adk gene that encodes an adenylate kinase has been determined. The secY gene of BCG has an open reading frame of 441 amino acids with homology to the SecY protein family. Comparative analyses of the deduced amino acid sequence of additional partial ORF revealed strong similarity to the known adenylate kinases.

Amino Acid Sequence↗
PubMed1997

Cloning of the human cDNA sequence encoding the NADH:ubiquinone oxidoreductase MLRQ subunit.

A cDNA clone encoding human NADH:ubiquinone oxidoreductase (complex I of mitochondrial respiratory chain) MLRQ subunit was isolated from human fetal liver cDNA library. The clone contained an open reading frame of 246 by which predicted a protein comprising 81 amino acids with a calculated molecular weight of 9,370 Da. The deduced amino acid sequence exhibited 95% homology (88% identity and 7% favored substitution) to that of bovine MLRQ subunit. Northern analysis revealed that the cDNA clone hybridized with a 0.7 kb mRNA species which was present in all tissues examined. The expression level of the 0.7 kb mRNA in heart, skeletal muscle, and brain was higher than in other organs. Human MLRQ cDNA could cross-hybridize with the genomic DNAs from various species.

Amino Acid Sequence↗
PubMed1996

Molecular cloning and expression of human Gal beta 1,3GalNAc alpha 2,3-sialytransferase (hST3Gal II).

A cDNA of human Gal beta 1,3GalNAc alpha 2,3-sialytransferase (hST3Gal II) which has been known to exhibit much more acceptor substrate preference for glycolipid than for O-linked oligosaccharides of glycoproteins, was isolated from the human liver cDNA library by plaque hybridization using the cDNA of mouse ST3Gal II (mST3Gal II) cloned previously as a probe. Comparative analysis of this cDNA with mST3Gal II indicates 89 and 94% homologies in the nucleotide and amino acid levels, respectively, between the two sequences in the predicted coding region. Northern analysis indicated that the expression of hST3Gal II mRNA is tissue-specific, it being prominent in skeletal muscle and heart, while that in lung and kidney is very low. This enzyme expressed in COS cells showed a similar activity with that of mST3Gal II.

Amino Acid Sequence↗
PubMed1996

Sequence analysis of the 5'-flanking region of the gene encoding human N-acetylglucosaminyltransferase III.

We have isolated and characterized the immediate (1651 bP) 5'-flanking region of the gene (GnT-III) encoding N-acetylglucosaminyltransferase III (GnT-III) from a human placental genomic library. Analysis of promoter elements shows a similarity to the 5'-flanking region of murine 1,4-galactosyltransferase. The sequence lacks obvious TATA elements and CCAAT boxes; however, putative regulatory sites, including 2 potential cAMP-response regulatory elements (CRE), 11 insulin-response element consensus sequences (IRE), 7 potential AP-2 binding sites, 2 SP1 consensus sequences (GC boxes) and 2 sequences similar to the half-palindromic glucocorticoid-responsive element (GRE), are present.

Amino Acid Sequence↗
PubMed1996

Cloning and characterization of cDNA for human adenylate kinase 2A.

We have isolated and characterized a cDNA clone encoding human adenylate kinase 2A (AK2A) from cDNA libraries of fetal liver origin. The complete nucleotide sequence of the cloned 889 nucleotide cDNA fragment indicated that the deduced gene product of human AK2A is composed of 239 amino acids with a molecular weight of 26 kD. Comparison of these nucleotide and amino acid sequences with the corresponding sequences of bovine AK2A and rat AK2 revealed a high degree of conservation. It showed 91% and 98% homologies in DNA and amino acid sequences, respectively, with bovine AK2A throughout the full open reading frame. RNA blot analysis revealed that three species of mRNA were present with approximate sizes of 3.4, 2.1, and 1.0 kb. This gene was expressed in E. coli cells and the recombinant protein was enzymatically active.

Adenylate Kinase↗
PubMed1995

Use of progesterone-3(O-carboxymethyl oxime)-horseradish peroxidase in a sensitive microtitre-plate EIA and its application to a visual membrane EIA of progesterone.

A simple method of visual membrane enzyme-immunoassay (EIA) for the detection of progesterone is described. When two types of progesterone-horseradish peroxidase (HRP) tracers were challenged for binding, in the presence of progesterone, to the monoclonal anti-progesterone antibody, 15A, coated on the microtitre plate, the HRP conjugated at the C-3 position (A-ring) of progesterone competed more effectively with progesterone to the binding site of the monoclonal antibody (mAb) than HRP conjugated at the C-11 position of the C-ring. By using this combination of mAb, 15A, and progesterone-3(O-carboxymethyloxime)-HRP (P-3CMO-HRP), we developed a visual membrane EIA system in which free progesterone in the sample could be quantified by the degree of color development. In this system, free progesterone competed with P-3CMO-HRP for binding sites of mAb immobilized on the nitrocellulose membrane. The stable grey color was formed on the surface of membrane for progesterone-negative and no color for progesterone-positive sample using 3,3'-diaminobenzidine (DAB) with Co2+ as an insoluble substrate solution. To examine whether tetramethylbenzidine (TMB) can substitute for DAB in membrane EIA, an experiment was conducted where TMB was used as an insoluble substrate.

3,3'-Diaminobenzidine↗
PubMed1995

Antibodies prevalence against HPV-6b and -16 recombinant fusion proteins in Korean patients with cervical neoplasia.

OBJECTIVES: This study was to investigate the adjunctive diagnostic utility of HPV fusion proteins from the sera in the patients with cervical neoplasia. Immunologic researches on host factors in HPV infection could contribute to better understanding of patho-physiologic mechanisms of cervical carcinogenesis, and provide valuable information for HPV vaccine development. METHODS: Prevalence of antibodies against human papillomavirus (HPV) in sera of the patients with carcinoma (n = 81), precancers (n = 25) of uterine cervix and normal controls (n = 40) in Korean women were investigated by Western blot immunoassay using partially purified TrpE fusion recombinant proteins for HPV-6b and HPV-16. RESULTS: In 81 patients with cervical cancer, 15 (19%) and 54 (67%) patients were positive for antibodies to at least one of the tested recombinant proteins related to HPV-6b or HPV-16, respectively. And in 25 patients with HPV-related squamous intraepithelial lesion (SIL) of cervix, 10 were positive for at least one of the tested antibodies for HPV-6b gene products (40%) and 11 were positive for HPV-16 related antibodies (44%). The prevalence rates of antibodies for HPV-6b in the sera of SIL patients were significantly higher than those from the sera of cervical cancer patients (p < 0.05). There was an inverse correlation between increasing the positivity against HPV-16 E6 protein and progression of cervical lesions, but there was no significant correlation between the positivities of the other antibodies to HPV-16 and the severity of disease. CONCLUSION: These results suggest that the recombinant proteins related to HPV-6b and HPV-16 could be useful in evaluation of the patients with HPV-related cervical lesions and these might play an adjunctive role in diagnosis and management of cervical neoplasia.

Antibodies, Viral↗
PubMed1993

Production and characterization of monoclonal antibody that simultaneously recognizes methamphetamine and its major metabolite.

A series of monoclonal antibodies (mAbs) that react with methamphetamine-bovine serum albumin (MA-BSA) were established by intrasplenic immunization method. Among established 36 clones, two typical mAbs, designated NK-1 and NK-2, were described. The inhibition assay of enzyme-linked immunosorbent assay (ELISA) analysis using methamphetamine analogs indicated that NK-1 showed considerable reactivity not only MA-BSA but also methamphetamine and its major metabolite, para-hydroxymethamphetamine (p-hydroxymethamphetamine). The cross-reactivity between NK-1 and the methamphetamine analogs with modified alkyl side chain, indicates that methyl groups of R5 and R7 in the methamphetamine molecules are important for the maximum affinity. The length of alkyl side chain on methamphetamine significantly affected the binding affinity of NK-1. The results may suggest that NK-1 will recognize not only methamphetamine but also the bridge part of the methamphetamine that binds the methamphetamine molecules to a carrier protein.

Animals↗
PubMed1993

Influence of the conjugation site on the specificity of monoclonal antibodies to progesterone and on the performance of direct enzyme immunoassay.

Monoclonal antibodies against progesterone conjugated to carrier protein through substituent on the A-ring (C3 position ) or the C-ring (C11 position) of progesterone were used in the enzyme immunoassay. Antibody specificities were determined by testing the ability of 11 represensitive steroids to displace labelled progesterone in a competitive enzyme immuno-assay (EIA) and a radioimmunoassay (RIA). Immunization with progesterone conjugated to BSA through substituent on the A-ring (C3) resulted in the formation of monoclonal antibody (mAb) which fairly specific for progesterone. While immunization with progesterone at the 11-position (C11) resulted in the mAbs which were very specific for progesterone. The best EIA system was developed by using mAb against progesterone-11 alpha -hemisuccinyl BSA and tracer of progesterone-3(O-carboxymethyl oxmine)-horseradish peroxidase. Our approach is to confirm the overall orientation of the steroid in the binding site. Immunobiochemical analysis of mAb suggested that the D-ring is substantially more buried in the binding pocket than the A-ring. Our assay was designed to use the reagent inactivating cholesterol binding globulin in serum so that the extraction of the hormone into organic solvent was unnecessary. Therefore, our assay system can detect directly and rapidly the progesterone level in serum within one hour.

Animals↗
PubMed1992

Solid-phase immunoassay using a flow cytometer: quantitative and qualitative determination of protein antigens and a hapten.

A fluoroimmunoassay employing a flow cytometer as the fluorescence-detecting device is described. Three kinds of antigens, murine immunoglobulin (Ig), human chorionic gonadotropin (hCG) and progesterone were chosen as examples of the assay using fluorescein-labeled antibodies. Cyanogen bromide-activated agarose beads were used as solid-phase supporters. The flow cytometric immunoassay was applied to both qualitative and quantitative analyses; determination of murine Ig isotypes, quantitative determination of Ig, hCG and a hapten, progesterone. This assay produced very reproducible and less-fluctuating data since thousands of particles in the assay were collected and processed to produce a single value for fluorescence intensities. Furthermore, the working range of the assay in terms of antigen concentration was much broader than that of enzyme immunoassay. Therefore, we believe that microparticles like agarose beads could be useful solid-phase supporters in immunoassay, and the flow cytometer could provide a reliable alternative to the fluorescence-detecting device in immunoassay.

Animals↗
PubMed1991

Simple enzyme immunoassay for the simultaneous measurement of whole choriogonadotropin molecules and free beta-subunits in sera of women with abnormal pregnancies or tumors of the reproductive system.

A multiple enzyme immunoassay (multi-EIA) was developed to quantify whole-molecule human choriogonadotropin (w-hCG) and free hCG beta-subunits (hCG-beta) simultaneously. A clone of a specific monoclonal antibody was coupled to solid phase; two other clones of different monoclonal antibodies were conjugated to horseradish peroxidase (HRP; EC 1.11.1.7) and alkaline phosphatase (AP; EC 3.1.3.1), respectively. These two enzyme conjugates were mixed together to measure w-hCG or hCG-beta, depending on the selection of the enzyme substrate. To measure w-hCG and hCG-beta simultaneously, both enzyme substrates were used with the blended enzyme conjugates. The assay is simple and reproducible, and can be completed within 2 h with high specificity and sensitivity. We measured w-hCG and hCG-beta in the sera of women with abnormal pregnancies and in patients with tumors of the reproductive system, and observed different hCG-beta/w-hCG ratios in patients with various types of trophoblastic tumors.

Antibodies, Monoclonal↗
PubMed1989

Type II collagen distribution in the ear of the developing chick embryo.

The localization of type II collagen was immunohistochemically studied in the developing chick ear using monoclonal antibodies. Type II collagen appeared under the basal lamina of the otocyst from developmental stages 14 to 16. In the otic capsule, endolymphatic duct, and semicircular canal membrane, type II collagen appeared in stage 23 or 24. From stages 28 to 29, type II collagen appeared in the primitive columella, endolymphatic sac, and fibrocartilaginous plate. Type II collagen was first observed in the crista ampullaris, basilar membrane, macula sacculi, and utriculi in stages 30 and 31. Type II collagen was not detected in the endolymphatic sac beyond developmental stage 37 and the amount of type II collagen in the otic capsule and columella decreased after stage 40. The wide distribution of type II collagen in the inner ear throughout the development of the chick embryo suggests that this collagen may act as a basic structural component of the ear.

Animals↗
PubMed1986

Infectious and non-infectious mutants of cauliflower mosaic virus DNA.

Mutants of cauliflower mosaic virus (CaMV), generated in vitro by modification of recombinant DNA plasmids containing the viral genome, either retained the ability to induce disease symptoms on turnip plants, produced less severe symptoms or failed to induce symptoms. Wild-type symptoms were produced by a variant CaMV DNA of the Cabbage S isolate that had 4 bp in open reading frame (ORF) III replaced with a 16 bp sequence. Less severe symptoms, due to a delay in symptom appearance relative to inoculation with wild-type DNA, were induced by a mutant with a frameshift mutation in ORF II (pSA103). CaMV DNA, recovered from plants infected with pSA103, contained a second mutation which restored the original translation reading frame. Nucleic acid hybridization to 'squishes' of leaf tissue from plants that had been inoculated with mutant DNAs that included DNAs modified in each of the six major ORFs of CaMV DNA revealed that only those plants that appeared diseased had detectable CaMV nucleic acid in uninoculated leaves. Replicated CaMV DNA was also not detected in non-encapsidated and virion DNA fractions from inoculated leaves of non-diseased plants.

Base Sequence↗
PubMedDate not supplied

Factors influencing collagen-induced autoimmune ear disease.

In 1981, the authors described a type II collagen-induced autoimmune ear disease (CIAED) model. The purpose of this study was to gather further evidence that this is a sound animal model to use in evaluating inner ear diseases. The temporal bone lesions of CIAED in Lewis and Wistar rats were characterized by the presence of sensorineural hearing loss with mild atrophy of the organ of Corti and spiral ganglion degeneration, vestibular dysfunction with vacuolar degeneration of the crista ampullaris, otospongiosis-like lesions in the tympanic annules, cochlear vasculitis, and eustachian tube disease. Both cellular and humoral immune responses to type II collagen were demonstrated. The induction of ear lesions depends on many factors. In general, animals immunized with antigens in complete Freund's adjuvant showed relatively more severe lesions than animals immunized with antigens in incomplete Freund's adjuvant, but the duration of the immunization seems to be a more important factor in reproducing severe lesions. The strain and the source of the animals are also important factors in autoimmune inner ear diseases, as is the condition of the host animals. Subclinical or clinical mycoplasma infection in the rat markedly reduced the incidence and severity of lesions in type II collagen-induced arthritis. Many researchers did not consider sialoductal adenovirus, widely present among laboratory rats, a lesion-producing factor in rats. Although many factors influence the induction and severity of CIAED, these animal models provide an excellent new avenue of inner ear research.

Animals↗