Electrolytic preparation of high dielectric thin films

Electrolytic formation techniques for high dielectric materials in thin films - barium salts - titanate, zirconate, and niobat

Electrolytic preparation of high dielectric films quarterly report, 3 aug. - 3 nov. 1964

Production of high dielectric films containing barium titanat

Electrolytic preparation of high dielectric films quarterly report, may 4 - aug. 3, 1965

Electrolytic preparation of high dielectric thin film coatings on refractory metal substrate

The preparation and characterization of phosphorylated derivatives of histidine

1. Phosphorylated derivatives of histidine were synthesized and studied in order to provide a better understanding of the chemistry of phosphohistidine-containing proteins. 1-Phosphohistidine, 1,3-diphosphohistidine, [alpha], 1,3-triphosphohistidine, and phosphorylated derivatives of [alpha]-N-acetylhistidine were prepared by reactions with POCl3 or phosphoramidate. The compounds were purified by ion-exchange chromatography and characterized by the phosphate: histidine ratio, electrophoretic behavior, and ultraviolet spectra.2. The rates of hydrolysis of these compounds, as well as 3-phosphohistidine, phosphoimidazole, and 1,3-diphosphoimidazole, were determined over a wide range of H+ concentrations. In strongly acidic solution all of the compounds appeared to be hydrolyzed by the same mechanism. In all cases the N-phosphoryl bond was hydrolyzed more readily if a proton or phosphoryl group were substituted on the other ring nitrogen, and histidine derivatives were less stable than the corresponding imidazole derivatives.3. For both mono- and diphosphoryl derivatives of histidine, the N-1 phosphoryl group was hydrolyzed and transferred to other imidazole compounds more readily than the N-3 phosphoryl group. The greater reactivity at the N-1 position is partially due to the presence of the protonated [alpha]-amino group.4. In aqueous solution, 1-phosphohistidine is rapidly converted to 3-phosphohistidine, histidine and inorganic phosphate.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33214/1/0000603.pd

A game to help students comprehend enzyme structure and mechanism of action

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/21849/1/0000252.pd

Vascular Changes Following Exercise-Induced Hyperthermia

Please view abstract in the attached PDF file

Coupling of dihydroriboflavin oxidation to the formation of the higher valence states of hemeproteins

SummaryThe reactions between hydrogen peroxide and hemeproteins have been coupled to the oxidation of dihydroriboflavin so as to provide a simple method for measuring the rate constant of hemeprotein peroxidation. Dihydroriboflavin rapidly reduces the higher oxidation states of iron and the hydroxy radicals which are the products of the hemeprotein / hydrogen peroxide reaction. The rapid reduction of these highly reactive compounds prevents the hemeproteins from undergoing irreversible chemical modifications and thus allows the kinetics of peroxidation to be studied. The rate constants at pH 7.2 and 23[deg]C for the peroxidation of horseradish peroxidase, myoglobin, and ferrocytochrome c are found to be 6.2 x 106, 7.5 x 104, and 8 x 103M-1s-1, respectively. These studies suggest that reduced riboflavin might efficiently protect cells from oxidative damage such as that occurring in inflammation and reperfusion injury.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29022/1/0000052.pd

Purification and structural studies of rabbit erythrocyte cytochrome b5

SummaryA single form of cytochrome b5 has been isolated in highly purified form from the cytosolic fraction of rabbit erythrocytes by sequential chromatography on DE-52 cellulose, Sephadex G-75, and DEAE-Sephadex A50. The cytochrome is structurally similar to the N-terminal, heme-binding domain of rabbit liver microsomal cytochrome b5. Like the liver protein, it is blocked at the amino terminus. Its amino acid composition is similar to that of residues 1-97 of the microsomal protein. With one exception, tryptic peptides derived from apo-cytochrome b5 of rabbit erythrocytes co-elute with the tryptic peptides obtained from a soluble hemepeptide fragment of microsomal cytochrome b5. These findings, together with amino acid sequence analysis of the carboxyl terminal tryptic peptides, identify the erythrocyte cytochrome b5 as a 97-residue peptide.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25110/1/0000542.pd

Isolation of an acid protease from rabbit reticulocytes and evidence for its role in processing redox proteins during erythroid maturation

A protease which generates a soluble hemepeptide from bovine liver microsomal cytochrome has been isolated from the membrane fraction of rabbit reticulocytes. Inhibition by pepstatin and an acidic pH optimum indicate that the protease belongs to the acid protease class. Little cytochrome -processing activity is observed in rabbit erythrocytes. We suggest that the protease may be involved in the processing which generates the proteins of the methemoglobin reduction system from their membrane-bound precursors during the maturation of the erythroid cell.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24341/1/0000608.pd

Soluble cytochrome b5 reductase from human erythrocytes

1. An enzyme that catalyzes the reduction of erythrocyte cytochrome b5 has been isolated from the supernatant fraction of erythrocyte hemolysates by chromatography on DEAE-cellulose, Amberlite CG-50, and Bio-Gel P-60.2. Erythrocyte cytochrome b5 reductase has been shown to contain FAD. Incubation of the reductase in the absence of EDTA results in both the appearance of flavin fluorescence and the loss of enzymatic activity with time.3. The reductase catalyzes the reduction of erythrocyte cytochrome b5 50 times faster with NADH than with NADPH. The apparent Km of NADH was calculated to be 1.6 x 10-6 M and the turnover number is 1280 moles of cytochrome b5 per min per mole of flavin. The reduction of electron acceptors proceeded in the following decreasing order of rate: K3Fe(CN)6, 2,6-dichlorophenolindophenol (DCIP), cytochrome b5, methylene blue, cytochrome c, O2, oxidized glutathione, and methemoglobin.4. The FAD prosthetic group, the substrate specificity, and the effect of ionic strength, pH, and EDTA on activity suggest that the reductase is the same enzyme as NADH dehydrogenase I, the enzyme lacking in many cases of congenital methemoglobinemia. The properties of the reductase, including its molecular weight, are very similar to those of the cytochrome b5 reductases solubilized from microsomes and mitochondria of other tissues.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34070/1/0000348.pd