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Biomedical subjects

T Takagi

Publications and source records attributed to T Takagi.

At least 883 records · Page 49Linked to original sources
PubMed1982

The use of the laser light scattering for the molecular weight determination of membrane proteins in surfactants.

A method is described for the determination of the molecular weight of the protein moiety of protein surfactant complexes using of low angle laser light (633 nm) scattering in combination with high performance porous silica gel chromatography, precision differential refractometry and differential UV absorption was described. The calibration curves in sodium dodecyl sulfate (SDS) and in a non-ionic surfactant, octaethyleneglycol dodecyl ether, using several reference proteins yielded linear lines. Molecular weight of porin oligomers and monomers, an intrinsic membrance protein that forms the permeability channel in the outer membrane of Escherichia coli, were calculated and were found to be 109,000 and 36,300, respectively in SDS and that of oligomers in octaethy leneglycol dodecyl ether was 114,200. Similarly, the molecular weights of maltoporin oligomers and monomers, which form maltose-maltodextrin specific channels, appeared to be 148,500 and 48,200, respectively, in SDS and that of oligomers in octaethyleneglycol dodeclyl ether was 149,000.

Chromatography, Gel↗
PubMed1981

A low-angle laser light scattering study of the association behavior of a major membrane protein of Rhodospirillum rubrum chromatophore at various concentrations of sodium dodecyl sulfate where polypeptides derived from water-soluble globular proteins are solubilized monomerically.

The major membrane protein of Rhodospirillum rubrum chromatophore could be solubilized in the presence of free sodium dodecyl sulfate (SDS) in concentration above 0.8 mM. At this concentration, the protein was highly associated to give a weight-averaged molecular weight as high as one million as determined by the low-angle laser light scattering technique. With the increase of free SDS concentration, the aggregates were progressively dissociated to give a molecular weight of 8300 at the critical micelle concentration of SDS. Three protein polypeptides derived from typical water-soluble globular proteins, bovine serum albumin, ovalbumin and beta-lactoglobulin, were found to be solubilized monomerically even at 0.8 mM free SDS. The results obtained suggest that there is substantial difference in the mode of solubilization between polypeptides derived from intrinsic membrane proteins and those from water-soluble globular proteins.

Bacterial Chromatophores↗
PubMed1981

Confirmation of molecular weight of Aspergillus oryzae alpha-amylase using the low angle laser light scattering technique in combination with high pressure silica gel chromatography.

Molecular weight of Aspergillus oryzae alpha-amylase (Taka-amylase A) was estimated to be 51,000 +/- 500 by the combined use of high pressure silica gel (TSK-GEL G3000SW) chromatography and the low angle laser light scattering technique. The study was carried out partly to assess the performance of the combined technique, and results obtained indicate that it is highly promising as a method to determined protein molecular weight both accurately and quickly.

Amylases↗
PubMed1981

Circular dichroic studies on the interaction between reduced nicotinamide adenine dinucleotide phosphate-adrenodoxin reductase and adrenodoxin.

Circular dichroic spectra of NADPH-adrenodoxin reductase, adrenodoxin and the complex between oxidized adrenodoxin reductase and oxidized adrenodoxin were studied. A 1 : 1 complex formation between adrenodoxin reductase and adrenodoxin resulted in the appearance of a distinct difference CD spectrum, which was obtained by subtraction of the sum of their CD spectra from the CD spectrum of the mixture of the two proteins. The difference CD spectrum showed a broad trough between 500 and 600 nm and CD extrema at 452, 383, and 350 nm. This spectrum may reflect a change in the environment of either or both of the protein chromophores. By applying the curve-fitting method to analyze the ellipticity change at 452 nm of the difference CD spectrum obtained on titration of a fixed amount of adrenodoxin reductase with various amounts of adrenodoxin, we directly obtained a value of 4.56 x 10(-7) M (S.D. 9.58 x 10(-8) M) as the dissociation constant of the oxidized complex. We also studied the change of the difference ellipticity induced by the addition of salt and obtained dissociation constants for the oxidized complex at various concentrations of NaCl. These values were larger than those obtained previously by kinetic methods, measurements of NADPH-cytochrome c reductase and NADPH-DCIP reductase activities. Further, we examined the relationship between the change of these activities on the addition of salt and the complex concentration calculated using the dissociation constant obtained in this study and found that the change of these activities could not be attributed simply to dissociation of the oxidized complex.

Adrenodoxin↗
PubMed1981

Comparative collagen biochemistry of bovine periodontium, gingiva, and dental pulp.

Cross-linking patterns of the collagen from bovine gingiva, periodontium, and dental pulp were analyzed chromatographically. The ratios of two main cross-links, dihydroxylysinonorleucine to hydroxylysinonorlecuine, were 0.18, 0.31, and 0.49 for the bovine gingiva, periodontium, and dental pulp collagen, respectively. These ratios are similar to that of skin collagen rather than that of bone and dentin collagen.

Amino Acids↗
PubMed1981

Studies on prolidase deficiency with a possible defect in collagen metabolism.

Skin collagen of a female patient with prolidase deficiency was examined for the distribution of borohydride-reducible cross-links and the proportion of type III to type I collagen. Patient's skin contained after reduction more dihydroxylysinonorleucine relative to hydroxylysinonorleucine and type III collagen than expected for normally matured skin. These findings suggest that collagen of the patient's skin failed to follow a time-related normal maturation process and the collagen metabolism was disturbed. The composition of urinary collagen metabolites was also unusual. On the the other hand, her asymptomatic brother with prolidase deficiency showed the normal urinary compositon of collagen matabolites. It is suggested that prolidase deficiency and defect in collagen metabolism independent of it are both responsible for clinical manifestation.

Collagen↗
PubMed1981

Location of an intermolecular crosslink in bovine bone collagen.

A peptide containing 59 amino acid residues with a stoichiometric amount of dihydroxylysinonorleucine (0.7 mole) and hydroxylysinonorleucine (0.2 mole) was isolated from reduced 3H labelled bovine bone collagen sequentially cleaved with CNBr and trypsin. Further cleavage of the isolated crosslinked peptide with periodate yielded a radioactive peptide of 45 residues and a non-radioactive peptide of 16 residues. From the characteristic amino acid composition of these peptides it was deduced that the peptide was derived from an intermolecularly crosslinked region between lysyl or hydroxylysl residues in the carboxy-terminal extension of alpha 1-CB6 (17C residue) and alpha 1-CB5 (87th residue). This finding supports the observation that the alpha 1-CB6 peak was prominent on carboxymethyl cellulose chromatography of the CNBr digest of bone collagen only after limited pepsin digestion, and is consistent with the results obtained from a smaller crosslinked peptide previously isolated from calf bone collagen.

Amino Acids↗