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Y F Yang

Publications and source records attributed to Y F Yang.

At least 91 records · Page 5Linked to original sources
PubMed1990

High-level expression of pig liver thioltransferase (glutaredoxin) in Escherichia coli.

We report the first high-level expression of a mammalian thioltransferase (glutaredoxin) in Escherichia coli. A NcoI site (CCATGG) was introduced into the cDNA encoding pig liver thioltransferase (glutaredoxin) by site-directed mutagenesis, in which the first G of the original sequence, GCATGG, was replaced by a C. The altered cDNA was cloned into an expression vector, plasmid pKK233-2, between the unique NcoI and HindIII sites and expressed in E. coli JM105 at a high level (8% of total soluble protein) after 6 h of isopropyl-beta-D-thiogalactopyranoside induction. The soluble and unfused product was measured by the thiol-transferase thiol-disulfide exchange assay and immunoblotting analysis. The recombinant enzyme was purified to a single band as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing. The amino acid composition of the expressed enzyme agreed with that of the known sequence of pig liver thioltransferase (glutaredoxin). N-terminal sequence analysis revealed that unlike the native pig liver protein which is N-acetylated, the recombinant enzyme was unblocked at the N terminus (alanine). Various kinetic properties of the recombinant enzyme with regard to the exchange reaction were identical with those of the native enzyme.

Amino Acids↗
PubMed1990

Expression, partial purification and immunogenicity of fragments of the knob protein of Plasmodium falciparum.

Three structural domains of the histidine-rich knob protein (KP) of Plasmodium falciparum were expressed in Escherichia coli. A single-step purification scheme was devised to obtain great enrichment of expressed polypeptides for use in subsequent experiments. Immune human sera from Africa, South-East Asia and South America were tested for reactivity with each of the expressed fragments. While the two fragments which represented the central and C-terminal regions of KP showed a strong reactivity with all the antisera which were tested, the N-terminal fragment which contains the repetitive histidine-rich sequences showed almost no reactivity.

Amino Acid Sequence↗
PubMed1989

Cloning and sequencing the cDNA encoding pig liver thioltransferase.

We report here, the first successful cloning and sequencing of a full-length cDNA gene (TT) encoding the pig liver thioltransferase (TT). The TT cDNA was obtained by screening a commercial (Clonetech) pig liver cDNA library in lambda gt11, using polyclonal antibodies raised in rabbits against pig liver TT. Two positive clones were identified in 3.5 x 10(5) recombinants. For verification, we successfully hybridized three oligodeoxyribonucleotide nucleotide probes, synthesized according to three different regions of the pig liver TT amino acid (aa) sequence, to both of the positive clones. In addition, the size of the TT beta-galactosidase fusion protein, produced by the positive clone, was consistent with the length of the cDNA. The TT cDNA was subcloned into the EcoRI site of M13mp18 replicative form and sequenced by the dideoxy chain-termination method using 35S-labeled nucleotides. The aa sequence deduced from the cDNA sequence is in exact agreement with the previously reported primary aa sequence, except that the N terminus should be N-acetylalanine followed by glutamine, rather than the reverse, as originally interpreted by conventional mass spectrometry fast atom bombardment analysis of the tryptic peptide corresponding to the first 8 aa residues.

Amino Acid Sequence↗
PubMed1989

Isolation of creatine kinase BB isoenzyme with high specific activity and adequate purity for radioimmunoassay from human placenta on preparative polyacrylamide gel electrophoresis.

This report describes the procedures for isolation of creatine kinase BB isoenzyme (CK-BB) from human placenta on preparative polyacrylamide gel electrophoresis. 2.5 mg of CK-BB was purified from a 100-g portion of the human placenta, which had a mean specific activity of 957 kU/g and a mean yield of 16%. The placenta CK-BB exhibited single protein bands on several electrophoretic techniques. In addition, both of the placenta and brain CK-BB preparations were individually iodinated and the identical immunological properties of both the CK-BB preparations were confirmed in radioimmunoassay.

Autoradiography↗
PubMed1989

Rapid purification of creatine kinase MB isoenzyme on preparative polyacrylamide slabs.

We describe a procedure for purification of creatine kinase (EC 2.7.3.2) MB isoenzyme (CK-MB) from human cardiac muscle by preparative electrophoresis on polyacrylamide gel. From a 50-g portion of human myocardium we isolated 21 mg of CK-MB, which had a specific creatine kinase activity of 405 kU/g. The CK-MB exhibited an enzyme band on polyacrylamide gel electrophoresis (PAGE) with staining for enzyme activity. The preparation showed single protein bands on sodium dodecyl sulfate--PAGE, pore gradient electrophoresis, and isoelectric focusing electrophoresis, the relative molecular masses of the subunit and of the whole enzyme being 43,000 and 86,000, respectively, and the isoelectric point being 5.0. In addition, the purified CK-MB showed desirable immunological specificity and affinity (K = 2.4 x 10(11) L/mol) when measured by radioimmunoassay.

Brain↗
PubMed1989

Persistant abnormal serum parathyroid hormone after renal transplantation: correlation between renal graft function.

Secondary hyperparathyroidism in uremia renal transplantation. We studied the i-PTH (immunoactive parathyroid hormone) of nineteen immunoactive parathyroid hormone) of nineteen patients before and after renal transplantation with average of 20 months post transplantation. In group I patients with normal i-PTH serum level had an significant lower serum level of creatinine than Group II with elevated abnormal i-PTH. While the calcium and phosphorus showed no significant difference between group I and Group II patients. We suggested that abnormal serum i-PTH level after renal transplantation after one year was closely related to renal graft function. This group of abnormal serum i-PTH should be closely monitored for their renal graft function.

Calcium↗
PubMed1988

Plasmodium falciparum: comparison of the genomic organization of the knob protein gene in knobby and knobless variants.

The genomic organization of the knob protein (KP) gene of knobby (K+) and knobless (K-) variants of the Thai isolate NT 108 and the Gambian isolate FCR-3 are compared. The restriction enzyme maps and the chromosomal location of the KP gene of K+ variants of both isolates are apparently identical. A comparison of the susceptibility of the KP gene to deletions and the extent of deletion of chromosomal DNA in K- variants of each geographical isolate suggests isolate-specificity of the stability of the deleted DNA sequences. With the exception of a mutant K- population of FCR-3, which could not be distinguished from K+ FCR-3, in all other K- variants of both geographical isolates the deletion of the KP gene was accompanied by the loss of several hundred base pairs of DNA from chromosome 2. The deletion resulted in the localization of the mutant KP gene in proximity to telomeric DNA sequences.

Animals↗
PubMed1988

Serum IgE in primary glomerular diseases and its clinical significance.

Total serum IgE was measured in 119 cases of primary glomerular diseases and 33 normal healthy persons. Statistically significant higher levels were noted in minimal change disease (MCD; median: 630 U/ml), IgM nephropathy (IgMN; 618 U/ml), focal glomerulosclerosis (FGS; 373 U/ml) and membranous glomerulonephritis (MGN; 144 U/ml). A higher level of serum IgE was noted in association with more frequent relapse or steroid resistance in MCD and IgMN and in FGS with nephrotic syndrome. A small group of IgA nephropathy with nephrotic range proteinuria was also noted to have extraordinarily high serum IgE. These findings suggest that IgE may play an important role in the pathogenesis of MCD, IgMN, and FGS and may serve as a prognostic indicator in terms of steroid responsiveness in MCD and IgMN.

Adolescent↗
PubMed1987

The primary structure of a Plasmodium falciparum polypeptide related to heat shock proteins.

A cDNA library constructed from ring-stage RNA isolated from Plasmodium falciparum FCR-3/Gambia was screened with immune human serum and two related positive clones were isolated. Nucleotide sequence analysis of these recombinant clones revealed an open translational reading frame for 681 amino acids with a calculated molecular weight of 74.3 kDa. The deduced amino acid sequence of the polypeptide shows extensive homology to several heat shock proteins (hsp) which have been described. Northern and Southern hybridization analysis indicates that P. falciparum has a second gene which shares common sequences with the hsp gene described in this study.

Amino Acid Sequence↗
PubMed1986

Glomerulonephritis in ankylosing spondylitis.

There have been a few reports suggesting the association between glomerulonephritis (GN) and ankylosing spondylitis (AS). The reported glomerulonephritides include IgA nephropathy, mesangial proliferative GN and membranous nephropathy. From January 1983, through December 1984, we observed 5 cases of GN among 116 cases of definite AS. Three of them were IgA nephropathy. The other two were mesangial proliferative GN, with IgM deposit in one case and isolated C3 deposit in another. Microscopic hematuria was observed in all of them. The renal function and 24-hour urine protein excretion were all within normal limits. Serum IgA level increased in all but the case of mesangial proliferative GN with IgM deposit. All except one had the antigen of HLA-B27. Serum IgA level was determined in 78 cases (86 estimations) of AS. The mean value was 399.6 +/- 15.0 mg/dl (mean +/- SE) (normal range: 100-350 mg/dl). Fifty-four of them (63%) had a value higher than 350 mg/dl. The interrelationship of AS and IgA nephropathy was discussed.

Adult↗