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C Franzblau

Publications and source records attributed to C Franzblau.

At least 163 records · Page 9Linked to original sources
PubMed1976

Effect of hydrophobic elastin ligands on the stress-strain properties of elastin fibers.

Alkyl sodium sulfates as well as sodium oleate previously shown to bind to insoluble elastin markedly decrease the tensile strength of fibers of ligament elastin. This effect correlates with the increasing number of carbon atoms in the detergent molecules. These data support previously proposed models which emphasize the importance of hydrophobic bonding to the elastic properties of this connective tissue protein.

Animals↗
PubMed1975

Isolation of soluble elastin from lathyritic chicks. Comparison to tropoelastin from copper deficient pigs.

Tropoelastin was isolated from the aortas of chicks rendered lathyritic by treatment with beta-aminopropionitrile. The soluble elastin was judged homogeneous by sodium dodecyl sulfate polyacrylamide gel electrophoresis and possessed an estimated molecular weight of 70000. Automated sequential analysis revealed that the N-terminal region of the chick tropoelastin is very homologous to tropoelastin isolated from copper-deficient piglets. N-terminal analysis of a trypsin digest of chick tropoelastin showed that tyrosine frequently is found adjacent to lysine residues. This positioning of tyrosine residues may be significant in terms of a possible regulatory role in elastin cross-link formation.

Amino Acid Sequence↗
PubMed1975

Effect of L-azetidine 2-carboxylic acid on growth and proline metabolism in Escherichia coli.

The effects of L-azetidine 2-carboxylic acid on growth and proline metabolism in a proline-requiring auxotroph of Escherichia coli are described. The homologue inhibited growth of the wild type and it, alone, did not substitute effectively for proline as a growth supplement for the mutant. In medium containing 0.05 mM proline, the addition of increasing amounts of homologue progressively inhibited growth of the wild type but stimulated growth of the mutant at homologue: proline ratios of 10 : 1 and 50 : 1. This suggested that the homologue exerted a "sparing effect" on proline in the mutant. The incorporation of L-[U-14C]proline and L-[3H]azetidine 2-carboxylic acid into hot trichloroacetic acid-insoluble material in the mutant was measured. Amino acid analysis of the insoluble material from cells incubated with radiolabeled proline alone revealed that proline was partially degraded and metabolized to other amino acids prior to incorporation into protein. The addition of unlabeled homologue to the incubation medium significantly reduced proline catabolism, suggesting that the homologue exerted a sparing effect on proline in this mutant. In medium containing unlabeled proline and radiolabeled L-azetidine 2-carboxylic acid, the homologue was incorporated both intact and partially degraded prior to incorporation into protein. Alanine was the major L-azetidine 2-carboxylic acid catabolite.

Amino Acids↗
PubMed1975

Allophycocyanin from the filamentous cyanophyte, Phormidium luridum.

Allophycocyanin from the filamentous cyanophyte, Phormidium luridum, was purified by ammonium sulfate fractionation and ion exchange chromatography on brushite columns. The specific absorption coefficient (E 0.1% 1cm) of purified allophycocyanin was 6.1 in distilled water and 7.3 in 0.05 M potassium phosphate buffer (pH 7). Absorption maxima of allophycocyanin occurred at 650, 618 (shoulder), 350, and 275 nm. Circular dichroic spectra displayed positive ellipticity bands at 655 and 625 nm, and a major negative ellipticity band at 340 nm. Computer analysis of the circular dichroic spectrum of allophycocyanin from 207 to 243 nm indicated that the secondary structure contained 60% alpha helix and 40% beta form. The estimated molecular weight of allophycocyanin on Sephadex G-200 columns at pH 7.0 was 155,000. Electrophoretic examination of allophycocyanin on sodium dodecyl sulfate polyacrylamide gels revealed two subunits, alpha and beta, with apparent molecular weights of 17,300 and 19,000, respectively. Densitometric analysis of unstained gels at 600 nm indicated that one phycocyanobilin chromophore was associated with each subunit. Treatment of allophycocyanin with 12% formic acid or 8 M urea and subsequent removal of the denaturant yielded a derivative with spectroscopic characteristics similar to phycocyanin. Subsequent incubation in phosphate buffer (pH 7), but not in acetate buffer (pH 5) or in water, was accompanied by a progressive reappearance of absorption maxima at 650 and 618 nm (shoulder), and positive ellipticity bands at 655 and 617 nm. Automated sequence analysis of allophycocyanin (a) showed that the sequence of amino acids at the amino terminus of the alpha and beta subunits is different, (b) showed that the subunits occur in a ratio of 1:1, and (c) demonstrated sequence homology at the amino terminus of allophycocyanin, phycocyanin, and phycoerythrin.

Amino Acids↗
PubMed1975

Incorporation of L-azetidine-2-carboxylic acid into hemoglobin in rabbit reticulocytes in vitro.

L-Azetidine-2-carboxylic acid is the naturally occurring lower homologue of L-proline. Reticulocytes from anemic rabbits incubated with DL-[14-C]azetidine-2-carboxylic acid synthesized radiolabeled hemoglobin, which when isolated from cell lysates co-chromatographed with unlabeled hemoglobin on Sephadex G-100 columns. Amino acid analysis of hemoglobin from reticulocytes incubated with DL-[14-C]-azetidine-2-carboxylic acid suggested that the homologue was incorporated into hemoglobin intact and unaltered. Alternatively, another amino acid analogue, 1-aminocyclopentane-[1-14-C]carboxylic acid, which is purported to be a valine antagonist, was not incorporated into hemoglobin under these conditions. Incubation of reticulocytes with 1, 5, and 10 mM L-azetidine-2-carboxylic acid reduced L-[U-14-C]proline (0.10 mM) incorporation into hemoglobin by 25, 58, and 72%, respectively. Conversely, 1.45 and 145 muM L-proline reduced radiolabeled azetidine-2-carboxylic acid (0.8 mM) in corporation into hemoglobin by 45 and 92%, respectively. Incorporation of L-[U-14-C]leucine and L-[U-14-C]lysine (0.1 mM each) into hemoglobin was unaffected at these concentrations of L-azetidine-2-carboxylic acid. These results suggest that L-azetidine-2-carboxylic acid is incorporated into hemoglobin without reducing the rate of globin synthesis in rabbit reticulocytes in vitro. The alpha and beta chains of hemoglobin into which [14-C]azetidine-2-carboxylic acid had been incorporated in rabbit reticulocytes in vitro were resolved electrophoretically on sodium dodecyl sulfate-polyacrylamide gels. The ratio of total radioactivity in the alpha and beta chains separately extracted from gels was in good agreement with the known 7:4 ratio of prolyl residues in the respective chains. Autoradiograms of two-dimensional tryptic peptide maps of rabbit globin into which either [14-C]azetidine-2-carboxylic acid or [14-C]proline had been incorporated showed nearly identical patterns of radioactivity. These results suggest that azetidine-2-carboxylic acid substitutes specifically for prolyl residues during in vitro hemoglobin synthesis in rabbit reticulocytes.

Amino Acids↗
PubMed1975

The alpha and beta subunits of Cyanidium caldarium phycocyanin: properties and amino acid sequences at the amino terminus.

Phycocyanin was isolated and purified from the unicellular alga, Cyanidium caldarium. Subunits were prepared on a Bio-Rex-70 column developed stepwise with urea solutions (pH 1.9). The alpha subunit eluted in 8 M urea and the beta subunit eluted in 9 M urea. The alpha and beta subunits displayed absorption maxima at 660, 354, and 277 nm in 8 M and 9 M urea. The alpha:beta ratio of total absorbance under the 660-nm peak was 0.56 suggesting an alpha:beta phycocyanobilin chromophore ration of 1:2. On calibrated sodium dodecyl sulfate gels, the alphs subunit had an estimated molecular weight of 15,500 plus or minus 1100 and the beta subunit has an estimated molecular weight of 18,300 plus or minus 300. Minimum molecular weights based on one histidine residue per subunit were 16,300 for the alpha subunit and 18,750 for the beta subunit. Phycocyanin displayed a single visible absorption maximum at 625 nm and two positive circular dichroic bands at 632 and 610 nm. The alpha and beta subunits displayed single visible absorption maxima at 618 and 600 nm and single positive circular dichroic peaks at 620 and 585 nm, respectively. Two-dimensional maps of tryptic digests of the alpha and beta subunits revealed distinct patterns of peptides each of which was consistent with the lysine and arginine composition of these polypeptides. Maps of tryptic digests of phycocyanin contained 25 major peptides (a total of 27 lysine and arginine residues). Automated sequence analysis of separated subunits revealed a 70% homology within the first 27 residues at the amino terminus of the alpha and beta subunits of C. caldarium phycocyanin.

Amino Acid Sequence↗
PubMed1974

A sex-linked defect in the cross-linking of collagen and elastin associated with the mottled locus in mice.

A genetic abnormality in collagen and elastin cross-linking resembling experimental lathyrism has been identified in mice. The defect is an X-linked trait, attributed to the mottled locus which also influences coat color. The affected mice have aneurysms of the aorta and its branches, weak skin, and bone deformities in a spectrum of severity varying with the alleles at the mottled locus. A defect in the cross-linking of collagen was demonstrated in the skin of the affected animals by a marked increase in collagen extractability and a reduced proportion of cross-linked components in the extracted collagen. A decrease in lysine-derived aldehyde levels was found in both skin collagen and aortic elastin similar to that found in lathyritic tissue. Furthermore the in vitro formation of lysine-derived aldehyde was reduced. Thus the cause of the connective tissue abnormalities in these mice appears to be a defect in cross-link formation due to an impairment in aldehyde formation.

Animals↗