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Biomedical subjects

B S Hong

Publications and source records attributed to B S Hong.

36 records · Page 2Linked to original sources
PubMed1983

Decrease of lactoferrin concentration in the tears of myotonic muscular dystrophy patients.

Tears from myotonic muscular dystrophy (MMD) patients and normal controls were analyzed for their tear proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Lactoferrin comprised about 18% of the total tear protein in MMD patients as opposed to about 27% in normals. The albumin content relative to total protein in MMD tears was about 25% while the same value for normals is 13%. The lactoferrin/albumin ratio, was about 0.8 for MMD patients and about 2.1 for normals.

Erythrocyte Membrane↗
PubMed1982

Biochemical and immunochemical evidence for the formation of a dimer of glial fibrillary acidic protein.

The glial fibrillary acidic protein isolated from calf brain white matter revealed two major protein bands with apparent molecular weights of 135 000 and 50 000, respectively. The heavy component could be enhanced by oxidation and completely converted to the light component by reduction. It was stoichiometrically established that one sulfhydryl group was present in each 50 000-dalton monomer and the disulfide linkage was involved in dimer formation. The results of the peptide mapping and the immuno-cross-reactivities of the two components indicated that they are identical proteins. We conclude that glial fibrillary acidic protein can occur as a dimeric structure which is formed by an intermolecular disulfide bond from two identical polypeptide chains.

Amino Acids↗
PubMed1982

Isolation and identification of a collagenolytic enzyme from the venom of the western diamondback rattlesnake (Crotalus atrox).

A collagenolytic enzyme, with a molecular weight of 58,000 daltons and isoelectric point of 5.1, was isolated and purified from the venom of the rattlesnake Crotalus atrox by Sephadex G-100 gel filtration followed by chromatography on DEAE-Bio-gel A. The enzyme released alpha-chains from beta-chains of the native collagen and cleaved in the helical region similar to other animal collagenases. The enzyme also hydrolyzed the PZ-peptide, however, it did not hydrolyze synthetic substrates for serine protease (such as TAME or ATEE). The enzyme had no hemorrhagic activity. Immunocross-reactivity suggested that only the venom from Crotalidae contain the enzyme.

Amino Acids↗
PubMed1982

Biochemical and surface characteristics of human tear proteins.

Pooled human tear samples were subjected to biochemical and surface chemical analyses. Gel filtration chromatography yielded four fractions. The second fraction was the most surface active, closely followed by the first. By ionic exchange chromatography, the first fraction obtained by gel filtration chromatography could be further separated into three subfractions. The second of these subfractions was found to be the most surface active, even surpassing the combined surface activity of all the tear components. Altogether eleven protein components were identified in human tears by gradient polyacrylamide gel electrophoresis with sodium dodecyl sulfate (SDS). Their molecular weights range from 16,000 to 400,000 daltons. Isoelectric focusing indicated that most of the tear proteins are negatively charged, whereas the rest are positively charged at physiological pH's.

Chromatography, Gel↗
PubMed1981

Isolation and characterization of a soluble, immunoactive peptide of glial fibrillary acidic protein.

A soluble immunoactive peptide with a molecular weight of 16 000 was isolated and purified from the cyanogen bromide digest of the insoluble 50 000 dalton glial fibrillary acidic protein by Sephacryl S-200 gel filtration followed by DEAE-Bio-gel A chromatography. The homogeneity of the peptide was established by SDS-polyacrylamide gel electrohporesis and isoelectric focusing. The peptide from several species showed immunocrossreaction with rabbit antibody to intact glial fibrillary acidic protein. The peptide has a pI value of 5.32. The amino acid sequence of 28 residues from the amino terminus of the calf peptide has been determined.

Amino Acid Sequence↗
PubMed1981

Quantitative analysis of collagen from normal developing corneas and corneal scars.

We measured the relative solubility of collagen in acetic acid after pepsin digestion and tentatively identified the types of collagen present in corneas of rabbits of various ages and in corneal scar tissue, using hydroxyproline assays and polyacrylamide gel electrophoretic analyses. More than 80% of the collagen in normal developing rabbit cornea was soluble after pepsin treatment; no more than 45% of that in two-week-old corneal scars was soluble. The predominant collagens in normal cornea and healing tissue were types I and AB. Type AB increased from 6% of the total collagen in fetal cornea to 11% in cornea from young adults. Collagen from two-week-old corneal wounds contained 16% type AB. Corneal type AB collagen was less soluble and more resistant to degradation by mammalian collagenase than was type I collagen. Unlike the normal cornea, in healing tissue the relative rate of synthesis of type I to type AB collagens did not correspond to their deposition. These results suggest a basic alteration in the molecular structure of the corneal scar, which may be instrumental in preventing the healing tissue from producing a normal, functioning organ.

Age Factors↗
PubMed1977

Sturctural homologies in mammalian neurofilament proteins.

Antibody has been prepared to purified neurofilament protein extracted from calf brain. This antibody crossreacts with brain and nerve extracts from all mammals tested but fails to crossreact with frog, cod and chicken nerve extracts. Thus the serologic homology of these neurofilament proteins appears to be restricted to the mammals. Structural similarities between the mammalian neurofilament protein are also indicated by the strong resemblance between iodinated peptide maps prepared from the electrophoretically purified neurofilament proteins.

Amino Acids↗
PubMed1977

Glutamine active site of formylglycinamide ribonucleotide amidotransferase. 1. Labeling of the enzyme with iodoacetate.

A two-step method for labeling the glutamine active site of formyglycinamide ribonucleotide (FGAR) amidotransferase from chicken liver has been developed in which reaction of all other reactive groups with unlabeled iodoacetate is followed by specific labeling of the glutamine site with radioactive reagent. A study of the reaction as a function of duration, temperature, and pH of the incubation as well as concentration of iodoacetate has revealed that two nonessential groups of the enzyme react in the presence of glutamine and that this modified enzyme is relatively resistant to further carboxymethylation. When this modified enzyme was incubated with radioactive iodoacetate in the presence of FGAR, ATP, and Mg2+ after removal of glutamine by dialysis, about 1 mol of radioactive iodoacetate was incorporated per mol of enzyme with inactivation. This method permits labeling of the active site for glutamine without the use of glutamine analogues.

Animals↗
PubMed1977

Glutamine active site of formylglycinamide ribonucleotide amidotransferase. 2. Amino acid sequence of labeled peptides.

The purification and characterization of two related peptides making up the glutamine binding site of formylglycinamide ribonucleotide amidotransferase from chicken liver have been presented. An amino acid residue(s) involved in binding glutamine to the enzyme was selectively labeled with [14C]iodoacetate. The labeled enzyme was reduced, carboxymethylated, and degraded by trypsin to a large radioactive peptide that yielded on acid hydrolysis only cysteine as a radioactive carboxymethylated derivative. The tryptic peptide was further digested with a protease from Streptomyces griseus. Two radioactive fractions (I and II) were obtained by gel filtration on Sephadex G-25. Furthermore, two 14C-containing peptides have been isolated from fraction I by the aid of ion exchange chromatography on AG 1-X2, AG 50W-X2 and DEAE-cellulose. Upon acid hydrolysis both peptides yielded only carboxymethylcysteine (CMCys), cystine, glycine, valine, aspartic acid, and glutamic acid. The partial sequences of the amino residues in these peptides, which are located at the glutamine binding site, have been established by the dansyl-Edman method. The sequences of amino acids of peptides a and b are Gly-Val-Cys([14C]CM)-Asp-Asx-Cys(CM)-Glx...and Gly-Val-Cys([14C]CM)-Asx-Asx..., respectively. The two peptides are undoubtedly derived from the same segment of the original protein.

Amino Acid Sequence↗
PubMedDate not supplied

Correlation of structural changes in parathyroid hormone with its vascular action.

The analysis of the spectrum of circular dichroism (CD) of methionine-oxidized bovine parathyroid hormone peptide, bPTH(1-34) revealed that approximately 43% of the orderly conformation (alpha-helix and beta-sheet) was converted into random coil structure. This peptide failed to elicit any hypotensive response in rats at any of the tested doses from 0.01 to 0.05 mg/ml. The blue shift of tryptophan fluorescence and the increase in the fluorescence intensity of the fluorescence probe 2-p-toluidinylnaphthalene-6-sulfonate (TNS) bound to the oxidized peptide indicated that the more hydrophobic environment was generated in the tryptophan domain as well as the molecule as a whole when the methionines in the peptide were oxidized. Modification of arginine with 1,2-cyclohexanedione (CHD) reduced 30% to 50% of the hypotensive action of the peptide hormone. Similar results in the increase of hydrophobicity of the arginine-modified peptide were also observed. These studies suggest that the conformational changes due to the methionine oxidation or arginine modification may be related to the inactivation of the vascular activity of bPTH(1-34).

Animals↗