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H Erdmann

Publications and source records attributed to H Erdmann.

At least 19 recordsLinked to original sources
PubMed1992

Purification and characterization of a NADH oxidase from the thermophile Thermus thermophilus HB8.

A NADH oxidase has been purified from the extreme thermophile Thermus thermophilus HB8 by several chromatographic steps. The purified enzyme was essentially homogeneous as judged by gel electrophoresis under denaturing conditions and by determination of the N-terminal amino acids sequence. It is a monomeric flavin-adenine-dinucleotide-containing flavoprotein with an apparent molecular mass of 25 kDa and an 1:1 ratio of FAD to the polypeptide chain. The purified enzyme catalyzes the oxidation of reduced NADH or NADPH with the formation of H2O2. The apparent Km values for NADH and NADPH are 4.14 microM and 14.0 microM (pH 7.2 at room temperature), respectively, with a sixfold greater kcat/Km values for NADH compared to NADPH. The enzyme uses O2 as an electron acceptor in the presence of either FAD, riboflavin 5'-phosphate or riboflavin as cofactor. In addition, the enzyme is able to catalyze electron transfer from NADH to various other electron acceptors (methylene blue, cytochrome c, p-nitroblue tetrazolium, 2,6-dichloroindophenol and potassium ferricyanide), even in the absence of flavin shuttles. No significant inhibition of the NADH oxidoreductase activity by superoxide dismutase was observed with these artificial electron acceptors, indicating that electron transfer occurs mainly from NADH directly to the electron acceptors, not via O2- as an intermediate. The purified NADH oxidase exhibits highest activity at pH 5.0 and is stable at elevated temperatures of up to 80 degrees C.

Amino Acid Sequence↗
PubMed1992

Purification and properties of lipase from Penicillium simplicissimum.

A Penicillium simplicissimum strain has been found to produce an inducible extracellular lipase. Triolein was the best inducer for the enzyme production with the highest activity being achieved after 48 h of incubation. The purified lipase showed a molecular weight of 56,000 by SDS-PAGE. The enzyme exhibited a high ratio of apolar amino acids. The lipase was stable in the pH range of 5-7 and at 50 degrees C for 15 min. The optimum assay conditions were 37 degrees C and pH 5.0. The enzyme showed a high stability in water immiscible organic solvents. Lipase from P. simplicissimum is nonspecific and hydrolyses each of the three bonds of triacylglycerols.

Amino Acids↗
PubMed1992

Solubilized substrates for the on-line measurement of lipases by flow injection analysis during chromatographic enzyme purification.

A flow injection analysis (FIA) system for the on-line measurement of lipases in chromatographic processes has been developed. The photometrically detectable substrates para-nitrophenylpalmitate, S,O,O'-tripropyryl-1-thioglycerol, and 1,2-O-dilauryl-rac-glycero-3-glutaric-resorufinester were investigated. Different detergents and qualities of assay emulsions were tested for optimal results in FIA applications. Emphasis was placed on increasing the stability of the assay emulsion. Lipases of different origin and specificity were detected. The linear detection range was adapted to the requirements of the chromatographic purification procedures. The connection of the FIA with a fast protein liquid chromatography system permitted the automatization of lipase purification by monitoring protein content, salinity, and enzyme activity of the effluent from column chromatography.

Animals↗
PubMed1989

The effect of recombinant human granulocyte-macrophage colony-stimulating factor on neutropenia and related morbidity in chronic severe neutropenia.

STUDY OBJECTIVE: To define the clinical and hematologic effects of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) on patients with chronic severe neutropenia. DESIGN: Open-label, phase II study of rhGM-CSF. SETTING: Inpatient hematology and surgery clinic at a university medical center. PATIENTS: Four consecutive patients with chronic severe neutropenia, which in two cases was complicated by severe infection, in one case by perianal fistula, and in one case by complete rectal prolapse. Two patients had chronic idiopathic neutropenia; one patient had congenital neutropenia (myelokathexis); and one patient had autoimmune neutropenia. INTERVENTIONS: The rhGM-CSF was given intravenously or subcutaneously at starting dosages of 150 to 1000 micrograms/m2 body surface area.d for 12 to 14 consecutive days. Two patients received a second course of daily rhGM-CSF treatment after a nontreatment interval of 14 to 20 days. MEASUREMENTS AND MAIN RESULTS: In all four patients, the absolute neutrophil counts increased from less than 0.25 x 10(9)/L to 3.2 to 19.2 x 10(9)/L within 2 weeks of beginning rhGM-CSF therapy. Two patients had life-threatening infections that resolved during therapy. The two other patients had major ano-rectal surgery during rhGM-CSF treatment and had no postoperative infections. CONCLUSIONS: In patients with chronic neutropenia, rhGM-CSF may increase neutrophil counts. This therapy may be a useful adjunct to antibiotic therapy for patients with infection and perioperatively for patients having anorectal surgery.

Adult↗
PubMed1986

The acidic peptide-specific type II protein kinases from the nucleus and the cytosol of porcine liver are distinct.

The second messenger-independent acidic peptide-specific protein kinase II (casein kinase II) from the cytosol of porcine liver has been purified to apparent homogeneity by using DEAE-cellulose, hydroxyl apatite, and phosphocellulose chromatography. The native enzyme has an apparent Mr of 150,000. After sodium dodecyl sulfate-gel electrophoresis a band of Mr = 39,000 and a slightly diffuse band of Mr = 27,000 were found indicating an alpha 2 beta 2 structure of this protein kinase. A thorough comparison with the corresponding enzyme from the nucleus was performed. The two enzymes differ in the subunit composition, as the nuclear enzyme is composed of subunits with a Mr of 95,000; they further differ in the heparin sensitivity and binding to blue dextran-Sepharose. Distinct differences in their nucleotide binding sites were found upon mapping with ATP analogs, although both enzymes utilize ATP as well as GTP. On the other hand, both enzymes phosphorylate identical sites in the casein variants beta A2 and alpha S1B at comparable rates. These results demonstrate for the first time the existence of distinct nucleus and cytoplasm specific type II "casein kinases".

Adenosine Triphosphate↗