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F Löffler

Publications and source records attributed to F Löffler.

At least 19 recordsLinked to original sources
PubMed1995

Dehalogenation of 4-chlorobenzoate. Characterisation of 4-chlorobenzoyl-coenzyme A dehalogenase from Pseudomonas sp. CBS3.

Pseudomonas sp. CBS3 is capable of growing with 4-chlorobenzoate as sole source of carbon and energy. The removal of the chlorine of 4-chlorobenzoate is performed in the first degradation step by an enzyme system consisting of three proteins. A 4-halobenzoate-coenzyme A ligase activates 4-chlorobenzoate in a coenzyme A, ATP and Mg2+ dependent reaction to 4-chlorobenzoyl-coenzyme A. This thioester intermediate is dehalogenated by the 4-chlorobenzoyl-coenzyme A dehalogenase. Finally coenzyme A is split off by a 4-hydroxybenzoyl-CoA thioesterase to form 4-hydroxybenzoate. The involved 4-chlorobenzoyl-coenzyme A dehalogenase was purified to apparent homogeneity by a five-step purification procedure. The native enzyme had an apparent molecular mass of 120,000 and was composed of four identical polypeptide subunits of 31 kDa. The enzyme displayed an isoelectric point of 6.7. The maximal initial rate of catalysis was achieved at pH 10 at 60 degrees C. The apparent Km value for 4-chlorobenzoyl-coenzyme A was 2.4-2.7 microM. Vmax was 1.1 x 10(-7) M sec-1 (2.2 mumol min-1 mg-1 of protein). The NH2-terminal amino acid sequence was determined. All 4-halobenzoyl-coenzyme A thioesters, except 4-fluorobenzoyl-coenzyme A, were dehalogenated by the 4-chlorobenzoyl-CoA dehalogenase.

Acyl Coenzyme A↗
PubMed1992

Purification and properties of 4-halobenzoate-coenzyme A ligase from Pseudomonas sp. CBS3.

The bacterial strain Pseudomonas sp. CBS3 possesses a multi component enzyme system which converts 4-chlorobenzoate to 4-hydroxybenzoate. In the first step 4-chlorobenzoate is activated in a coenzyme A, ATP and Mg(2+)-dependent reaction to 4-chlorobenzoyl-coenzyme A. ATP is cleaved thereby into AMP and pyrophosphate. The involved 4-chlorobenzoate-coenzyme A ligase was purified to apparent homogeneity by a 6-step purification procedure. The native enzyme had an apparent molecular mass of 115000 Da and was composed of two identical polypeptide subunits of 57 kDa. The enzyme displayed an isoelectric point of 5.3. The maximal initial rate of catalysis was achieved in 100mM Tris/HCl or Tricine/NaOH buffer, pH 8.4, at 35 degrees C. Under these conditions the apparent Km values for ATP, coenzyme A and 4-chlorobenzoate were 2.4 to 3.5 mM, 0.11 to 0.19mM and 0.05 to 0.065mM, respectively. Vmax was 111.6 mumol/(min x mg protein). The N-terminal amino-acid sequence was determined. 4-Halobenzoates were preferentially converted to the corresponding thioesters. Therefore, the enzyme was named 4-halobenzoate-coenzyme A ligase.

Adenosine Triphosphate↗
PubMed1991

Identification of 4-chlorobenzoyl-coenzyme A as intermediate in the dehalogenation catalyzed by 4-chlorobenzoate dehalogenase from Pseudomonas sp. CBS3.

The intermediate in the reaction catalyzed by 4-chlorobenzoate dehalogenase from Pseudomonas sp. CBS3 was identified as 4-chlorobenzoyl-CoA. One component of 4-chlorobenzoate dehalogenase worked as a a 4-chlorobenzoyl-CoA ligase catalyzing the formation of 4-chlorobenzoyl-CoA from 4-chlorobenzoate, coenzyme A and ATP. This intermediate was detected spectrophotometrically and by HPLC. 4-chlorobenzoyl-CoA was the substrate for the dehalogenase component, which catalyzed the conversion to 4-hydroxybenzoate with concomitant release of coenzyme A.

Adenosine Triphosphate↗
PubMed1991

Dehalogenation of 4-chlorobenzoate by 4-chlorobenzoate dehalogenase from pseudomonas sp. CBS3: an ATP/coenzyme A dependent reaction.

Pseudomonas sp. CBS3 was grown with 4-chlorobenzoate as sole source of carbon and energy. Freshly prepared cell-free extracts converted 4-chlorobenzoate to 4-hydroxybenzoate. After storage for 16 hours at 25 degrees C only about 50% of the initial activity was left. Treatment at 55 degrees C for 10 minutes, dialysis or desalting of the extracts by gel filtration caused a total loss of the activity of the 4-chlorobenzoate dehalogenase. The activity could be restored by the addition of ATP, coenzyme A and Mg2+. If one of these cofactors was missing, no dehalogenating activity was detectable. The amount of 4-hydroxybenzoate formed was proportional to the amount of ATP available in the test system whereas CoA served as a real coenzyme. A novel ATP/coenzyme A dependent reaction mechanism for the dehalogenation of 4-chlorobenzoate by 4-chlorobenzoate dehalogenase from Pseudomonas sp. CBS3 is proposed.

Adenosine Triphosphate↗
PubMed1991

Resolution of 4-chlorobenzoate dehalogenase from Pseudomonas sp. strain CBS3 into three components.

Extracts of Pseudomonas sp. strain CBS3 grown with 4-chlorobenzoate as sole carbon source contained an enzyme that converted 4-chlorobenzoate to 4-hydroxybenzoate. This enzyme was shown to consist of three components, all necessary for the reaction. Component I, which had a molecular weight of about 3,000, was highly unstable. Components II and III were stable proteins with molecular weights of about 86,000 and 92,000.

Hydrolases↗
PubMed1990

Cloning and DNA sequence analysis of a polygalacturonase cDNA from Aspergillus niger RH5344.

A 1319 bp long cDNA encoding for a polygalacturonase (EC 3.2.1.15) from Aspergillus niger RH5344 comprises a single open reading frame of 1089 bp which includes the mature protein of 362 amino acids and an NH2-terminal signal peptide of 27 amino acids. The directly determined peptides of the mature polygalacturonase confirmed the sequence information deduced from the cDNA.

Amino Acid Sequence↗
PubMed1990

Rapid protein purification using phenylbutylamine-Eupergit: a novel method for large-scale procedures.

Electrophoretic desorption was used to compare the protein binding capacities of some hydrophobic adsorbents [the phenylbutylamine (PBA) derivatives of Eupergit C and agarose and Phenyl-Sepharose] for low-pressure chromatography. The highest capacity was observed for the bifunctional adsorbent PBA-Eupergit. The hydrophobically adsorbed proteins can be selectively desorbed by decreasing the pH of the eluent due to electrostatic repulsion between positive charges on the adsorbed proteins and positively charged secondary amines on the adsorbent. This was used to purify 1500 U penicillin amidase from E. coli homogenates per gram wet weight of PBA-Eupergit in 50 adsorption-desorption cycles without organic solvents (greater than 90% yield, purification factor = 5.3).

Adsorption↗
PubMed1987

[Correlation of sonomorphologic placental maturity with the L/S ratio and creatinine level in the amniotic fluid].

With 184 L/S-ratio determinations and 132 creatinine determinations in amniotic fluid we tried to show a connection between these parameters and sonographically provable changes of placental structures. We found no relationship between placental grading and fetal lung and renal maturity by statistical processing of the results, considering gestational age. There is between L/S-ratio and creatinine determinations no statistical relationship, too.

Amniotic Fluid↗
PubMed1986

Immunological cross-reactivity of cultured rat hippocampal neurons with goldfish brain proteins synthesized during memory consolidation.

Ependymins are goldfish brain glycoproteins exhibiting a specifically enhanced rate of synthesis when the animals adopt a new pattern of swimming behavior. With specific antisera against ependymins it has become possible to look for ependymin-like immunoreactivity in other animal species, both qualitatively by immunofluorescence staining and quantitatively by radioimmunoassay. Ependymin-like immunoreactivity was detected not only in other fish but also in rat brain. In the rat radioimmunoassay measurements were highest for the hippocampal formation and for cultured neurons derived from the embryonic hippocampus. Immunofluorescence staining was performed on various cell culture systems derived from rat brain, in order to establish which cell type contains the antigen. Only neuronal cell populations reacted with the anti-ependymin antisera. Cells derived from embryonic rat brain hippocampus which resembled pyramidal neurons stained particularly bright for ependymin-like immunoreactivity. The antigenic material was distributed throughout the cytoplasm including the neuronal extensions. Various neuron-specific antisera have been used to counterstain the cells containing ependymin-like immunoreactivity.

Animals↗
PubMed1986

[Sonographically detectable changes in placental structures in pregnancy. 4. Statistical comparison of the frequency distribution of placental stages 0-3 in newborn infants in a pregnancy of 37-42 weeks duration].

Among women with a duration of pregnancy between 37 and 42 gestational weeks procentual frequency, confidence intervals of O. Bunke, pounts of separability and areas of unsharpners were analysed. 1412 sonographical examinations were done in 645 pregnant women. Stage 0 was found statistically significant more frequent with error of probability alpha = 0.05 until the 30. week of pregnancy, stage 1 between the 21. and 36. week of pregnancy, stage 2 between the 33. and 36. gestational week and stage 3 in 37. and 38. week. Transformation (areas of unsharpness) from stage 0 to stage 1 occurs between the 24. and 32. gestational week, from stage 1 to stage 2 between the 31. and 34. week, from stage 2 to stage 3 between the 36. and 42. gestational week.

Birth Weight↗
PubMed1986

[Sonographically detectable changes in placental structures in pregnancy. 5. Statistical comparison of the frequency distribution of placental stages 0-3 in newborn infants in a pregnancy of less than 37 weeks duration].

The analysis of sonographically provable changes of placental structures in 97 pregnant women (202 examination) shows in cases with a duration of pregnancy less than 37 gestational weeks that stage 0 could be found statistically significant more frequent until the 32nd week of pregnancy, stage 1 in the whole pregnancy, stage 2 and 3 between the 29. and 36. gestational week. Stage 0 and 1 don't effect prematurity; however stages 2 and 3 could be proved before the 32nd or 34th week of pregnancy in 41 or 100% of examination respectively and effect a premature birth. Stage 2 could be proved 2,8 times more frequent and stage 3 4 times more frequent in premature babies than in newborns with a normal duration of pregnancy.

Birth Weight↗
PubMed1986

[Sonographically detectable changes in placental structures in pregnancy. 6. Effect of sonographic placental morphology on premature labor and intrauterine growth retardation].

Influence of sonographically demonstrable changes of placental structure on prematurity and intrauterine retardation was analysed and concerning its statistical rehability in 807 gravids. While the stages 0 and 1 don't effect prematurity and intrauterine retardation, the stage 2 is accompanied premature infant of normal birthweight if proved before the 32nd week of pregnancy. If stage 3 appears before the 34. week of pregnancy we found in 30.6% a small for date newborn, in 64% a normal weight and in 80% a small for date premature newborn. In comparison with the normal weight newborn the difference is statistically significant with an error probability of alpha = 0.05.

Birth Weight↗
PubMed1986

[Retroperitoneal ganglioneuroma as a cause of obstructed labor].

The case of a primigravida is reported who was operated on for a retroperitoneal ganglioneuroma at the age of 12. At that time the tumor surgically could not be completely removed because of its size and anatomical location in relation to the backbone and the large blood vessels. A renewed tumour growth was observed in the course of the years. At the end of pregnancy the tumour proved to be an obstruction to the labour process.

Adult↗
PubMed1986

[Lung edema as a complication of tocolysis in twin pregnancy].

It was reported about a case of acute pulmonary oedema during tocolytic therapy with beta 2-stimulator Fenoterol. The aetiologic factors of the isotonic hyperhydration by beta-mimetic drugs, medicamentous influences and favoured factors have been discussed. Diagnostic and therapeutic consequences have been concluded.

Adult↗
PubMed1986

[Diagnostic and therapeutic aspects of pelvic vein thrombosis in pregnancy].

Deep pelvic venous thrombosis is a severe complication during pregnancy and requires an early diagnosis and an adequate well-timed therapy. 12 pregnant women with thrombosis of deep pelvic veins have been registered ++ over a period of 10 years. Diagnosis was secured with phlebography in 5 of these cases. It is reported about the necessity and the x-ray exposure of the examination. Treatment of choice is the heparin-longtime-therapy 90 per cent of our cases have been cured successfully.

Adolescent↗
PubMed1985

Selective increase of R-I subunit of cyclic AMP-dependent protein kinase in glia-rich primary cultures upon treatment with dibutyryl cyclic AMP.

Levels of cyclic GMP-dependent protein kinase and of the subunits (R-I, R-II and C) of cyclic AMP-dependent protein kinase were determined in two types of neural primary cell cultures that were either treated or not treated with dibutyryl cyclic AMP. Astroglia-rich cell cultures from newborn rat brain responded to exposure to dibutyryl cyclic AMP by a 2-3-fold increase in the level of R-I subunit, as demonstrated by two radioimmunological procedures, while the levels of the other subunits (R-II and C) and of cyclic GMP-dependent protein kinase remained unaffected. In contrast, neuron-rich cell cultures from embryonic rat brain did not display such a change in the level of R-I subunit. Thus, the elevation in the level of R-I elicited by dibutyryl cyclic AMP in normal non-malignant neural cells in culture was restricted to glial rather than neuronal cells.

Animals↗