Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.55 (PTR)
 433 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This work describes fluorescence yield measurements in suspensions of strains of Rhodospirillum rubrum and Rhodopseudomonas sphaeroides in which the iron . quinone complex (X) was chemically reduced (state [PIX-]; P is the reaction center bacteriochlorophyll dimer, I is the long wavelength bacteriopheophytin), and compares these with the fluorescence observed when all the traps are open (state [PIX]) and with the fluorescence observed when all the traps are closed (state [P+IX]). At 77 K the amplitude and the shape of the fluorescence emission spectrum in [PIX-] are identical to those observed in [PIX]. This is a strong indication that all the extra fluorescence observed at room temperature in [PIX-] is, in fact, caused by an efficient back reaction [P+I-X-] leads to [P*IX-]. Using an equation similar to the original Vredenberg-Duysens relationship (Vredenburg, W.J. and Duysens, L.N.M. (1963) Nature 197, 355-357) but now assuming that a single reaction center has a probability pt of trapping an excitation and (1--pt) of re-emitting it to the surroundings, we are able to calculate pt as a function of the temperature by measuring the fluorescence in [PIX], [PIX-] and [P+IX] as a function of the temperature. The calculated pt values agree reasonably well with triplet yields measured in isolated reaction centers. Finally, we have measured the reaction center triplet yield (PTR) in intact systems and we have shown that the sum of the triplet yield and the remaining loss processes (PL) in the antenna bacteriochlorophyll including the bacteriochlorophyll dimer (such as fluorescence, internal conversion or direct triplet formation) is approximately constant; if we assume that at 77 K the only process which occurs in the reaction center is the formation of a reaction center triplet, than PTR + PL=1. The energy barrier between [P*IX-] and [P+I-X-] was estimated to be 0.11--0.15 eV for a set of preparations.
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PMID:Bacteriochlorophyll fluorescence of purple bacteria at low redox potentials. The relationship between reaction center triplet yield and the emission yield. 9 54

The induction by adenovirus-12 of a site-specific gap and assignment of the chimpanzee genes for thymidine kinase and galactokinase were studied by utilizing chimpanzee-mouse hybrid cells. It has been shown that adenovirus-12 induces a specific gap in the long arm of human chromosome 17 (HS 17); with chimpanzee-mouse hybrid cells the specific gap appears on the short arm of the chimpanzee homolog [PTR 19 (HS 17)] of HS 17. This result supports the proposed relationship of HS 17 to PTR 19 (HS 17) by means of a pericentric inversion. The chimpanzee thymidine kinase and galactokinase genes were assigned to PTR 19 (HS 17), further confirming the homology to HS 17. Other syntenic relationships and gene assignments were consistent with proposed homologies between chimpanzee and human chromosomes.
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PMID:Genetic homology between man and the chimpanzee: syntenic relationships of genes for galactokinase and thymidine kinase and adenovirus-12-induced gaps using chimpanzee-mouse somatic cell hybrids. 19 54

Patients suffering from acute schizophrenia are subjected to treatment according to different therapy standards, depending on the individual hospital. Hence, the present study aimed at a comparative investigation of the effects and side effects of fluphenazine dihydrochloride administered to 51 acutely diseased schizophrenics via the intravenous, intramuscular and oral routes. It was also interesting to record the assessment of efficacy, painfulness and, as the case may be, repeated selection of the form of application concerned, by the patients themselves. Finally, we also investigated the relations between the age of the patients, duration of previous hospitalisation, and the effects achieved with the three application forms. Documentation was effected via the following examination instruments described and recommended by the National Institute of Mental Health (NIMH), USA; CGI, BPRS, Dotes, APDI and PTR.
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PMID:[Comparative investigation of action and side effects in intravenous, intramuscular and oral application of fluphenazine dihydrochloride (author's transl)]. 50 43

In rats with unilateral carotid artery ligation pyramidal tract responses were studied during hypoxia and during trimethaphan-induced hypotension. Observations on EEG activity during hypoxia suggest that unilateral carotid artery ligation produces a more severe perfusion defect in lateral portions of the hemisphere. During hypoxia and during trimethaphan-induced hypotension indirect PTRs disappeared first from the hemisphere on the side of carotid artery ligation and next from the opposite hemisphere. This was followed by loss of direct PTRs in the same order. Animals could not be resuscitated once the direct PTR from the non-ligated hemisphere had disappeared. Hypotension appears to be a late contributing factor in impairing electrocerebral activity during hypoxia in this study.
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PMID:Pyramidal tract responses (PTR) during hypoxia and hypotension. 96 Jan 74

Several physical properties of the first four enzymatic activities of the tryptophan pathway were examined using gel filtration and ion exchange chromatography. Five different patterns were noted. Differences in the anthranilate synthetase (AS) and phosphoribosylanthranilate transferase (PRT) defined these patterns. In all the organisms studied phosphoribosylanthranilate isomerase and indoleglycerol phosphate synthetase co-eluted from both diethylaminoethyl-cellulose and G-200 and thus probably are contained in a single polypeptide of 50,000 daltons. An AS-PRT complex was found in Citrobacter species, Enterobacter cloacae, and Erwinia dissolvens. In all the other bacteria examined AS and PTR were separate molecules. In Serratia marcescens, S. marinorubra, and Enterobacter liquefaciens, AS was 140,000 daltons and PRT was 45,000 daltons. In Erwinia carotavora and Enterobacter hafniae the AS was the same size as the Serratia species but the PRT was larger at 67,000 daltons. Two Proteus species had an AS and PRT of the same size as E. carotavora and E. halfniae but the Proteus AS was different in that it partially dissociated upon gel filtration. Aeromonas formicans was unique in its possession of an AS with a molecular weight of 220,000. The PRT of A. formicans was found to elute at 67,000 daltons. Possible paths of evolution of the tryptophan enzymes are discussed in terms of the results of this study. The results presented here are also considered with respect to existing taxonomic schemes of the enteric bacteria.
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PMID:Tryptophan biosynthetic pathway in the Enterobacteriaceae: some physical properties of the enzymes. 111 88

In combined biochemical and functional studies it has been possible to show that ergocornine (0.5-5 mg/kg) and the ergolene derivative (5R,8R)-8-(4-p-methoxyphenyl-1-piperazinylmethyl)-6-methylergolene (PTR 17402; MPME) (0.25-5 mg/kg) reduce in a dose-dependent way brain 5-hydroxytryptamine (5-HT) turnover in rat as evaluated with the tryptophan hydroxylase inhibitor, alpha-propyl-dopacetamide (H 22/54), whereas 2-Br-alpha-ergocryptine (CB 154; Br-EC) had no effect on brain 5-HT turnover. Effects on 5-HT receptor activity were evaluated using the extensor hindlimb reflex of acutely spinalized rats. It was found that ergocornine increased the 5-HT receptor activity independent of presynaptic 5-HT stores and that it didnot have any effects on uptake, retention and spontaneous overflow of 3-H-5-HT in vitro but reduced the fiedl stimulation-induced release of 3-H-5-HT in vitro. Therefore, it is suggested that ergocornine is a 5-HT recpetor-stimulating agent, an effect which may lead to reduction of nervous impulse flow in the 5-HT neurons and subsequently of 5-HT release and turnover. MPME, on the other hand, seems to increase 5-HT receptor release of 5-HT stores, mainly from extragranular sites. Thus, the increase in extensor reflex activity found after MPME was reduced by reserpine and H 22/54 and enhanced by nialamide and in vitro MPME markedly increased 3-H-5-HT overflow in cortical slices of nialamide-pretreated rats and inhibited uptake and retention of 3-H-5-HT (EC50 equals 1.6 times 10-minus 6 M) in cortical slices of normal rats. Inhibition of the 5-HT membrane pump does not seem to be of any major importance, since chlorimipramine was only weakly active on the extensor reflex in the pharmacological models used and since MPME did not block but rather enhanced the 5-HT depletion caused by 4-methyl-alpha-ethyl-m-tyramine. It is suggested that MPME is a releaser of extragranular 5-HT stores leading to increased 5-HT receptor activity and reduction of 5-HT turnover in the same way as indicated for ergocornine. This new ergolene derivative may represent a new class of antidepressant drugs acting via release of extragranular 5-HT stores.
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PMID:Effect of ergot drugs on central 5-hydroxytryptamine neurons: evidence for 5-hydroxytryptamine release or 5-hydroxytryptamine receptor stimulation. 117 34

In order to produce biologically active 1,6-anhydro-muropeptides in large amounts by enzymatic degradation of isolated bacterial murein polymer highly specific periplasmic murein-metabolizing enzymes from Escherichia coli are made available. The genes slt, dacB, and mepA, encoding the soluble lytic transglycosylase (Slt), the penicillin-sensitive DD-endopeptidase (PBP4), and the penicillin-insensitive murein endopeptidase A (MepA), were independently fused to the N-terminal encoding sequence of staphylococcal protein A (SpA) under control of the temperature-inducible phage lambda pR promoter. The SpA fusion proteins were stably over-produced at high levels in E. coli upon temperature induction at 42 degrees C and account for 3% (5 mg SpASlt/l culture), 3% (5 mg SpAPBP4/l culture), and 0.3% (0.5 mg SpAMepA/l culture) of total protein. The SpA fusion proteins, immobilized on IgG Sepharose, are proteolytically sensitive, in vitro, resulting in complete degradation of the SpA portion of the fusion proteins and release of the murein hydrolases in intact and enzymatically active form into the supernatant. Proteolytic degradation could be prevented by p-hydroxymercuribenzoic acid (PHMB) or ethylenediaminetetraacetate (EDTA) suggesting the involvement of the periplasmic protease Pi from E. coli. The immobilized fusion proteins were enzymatically active and could be used for the batch production of biologically active 1,6-anhydro-muropeptides, which were successively separated on HPLC. Isolated murein polymer was degraded quantitatively to monomeric 1,6-anhydro-muropeptides when immunoglobulin G (IgG)-SpASlt was used in combination with IgG-SpAMepA. A combination of IgG-SpASlt with IgG-SpAPBP4 left the 1,6-anhydro-dimers and oligomers being cross-linked via an LD-peptide bond (m-DAP-m-DAP) uncleaved.
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PMID:Enzymatic preparation of 1,6-anhydro-muropeptides by immobilized murein hydrolases from Escherichia coli fused to staphylococcal protein A. 136 91

The enzymatic and biochemical properties of human insulin-degrading enzyme and Escherichia coli protease III have been compared. Both enzymes were found to degrade insulin in such a way that its receptor binding activity was rapidly lost but its precipitability in trichloracetic acid was only slightly decreased. Both enzymes were also found to be inhibited by chelating agents. The bacterial enzyme, which could be purified in large amounts, was found to contain 0.6 mol of zinc per mol of enzyme but no detectable manganese. The mammalian enzyme but not the bacterial one was inhibited by a sulfhydryl alkylating agent. The two enzymes also differed in substrate specificity. The mammalian enzyme degraded insulin much better than insulin-like growth factor II, whereas the bacterial enzyme degraded them equally. The mammalian enzyme could be labeled by cross-linking to insulin = bombyxin II much greater than insulin-like growth factor I and II much greater than relaxin, while the bacterial enzyme was labeled by insulin-like growth factor II greater than insulin = insulin-like growth factor I much greater than relaxin much greater than bombyxin. Finally, sucrose gradient centrifugation and cross-linking studies both in vitro and in vivo indicated that active human enzyme partially existed as a homo- or heterodimer, whereas the bacterial enzyme was active as a monomer.
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PMID:Comparison of the enzymatic and biochemical properties of human insulin-degrading enzyme and Escherichia coli protease III. 173 42

On the basis of a statistical analysis of an alignment of the amino acid sequences, a new superfamily of metalloendopeptidases is proposed, consisting of human insulinase, Escherichia coli protease III and mitochondrial processing endopeptidases from Saccharomyces and Neurospora. These enzymes do not contain the 'HEXXH' consensus sequence found in all previously recognized zinc metalloendopeptidases.
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PMID:Homologues of insulinase, a new superfamily of metalloendopeptidases. 202 23

Rat thymic cultures have been established in order to analyse the morpho-functional characteristics of thymic epithelial and non-epithelial cells in vitro. Stromal cultures, originating from implanted thymic fragments, consist of fibroblasts occupying most of the culture surface, epithelial cells forming discrete colonies, thymocytes and bone marrow-derived cells. Epithelial cells show a low class II MHC antigen expression, which is highly increased in semi-adherent cells, and do not interact with thymocytes. Thymocytes proliferate extensively at the beginning of the culture, but almost disappear at the end of the first week; however, restarting of thymocyte proliferation occurs during the second week of culture. Bone marrow-derived cells include ED- Ia+ CR3- IL-2R- dendritic cells (DC), ED+ Ia+ CR3+ IL-2R+ non-adherent thymic phagocytic cells (PTR) and ED+ Ia- CR3- IL-2R- adherent type 1 and 2 macrophages, derived from PTR. Both PTR and DC establish lympho-stromatic complexes with thymocytes present in the cultures. These results suggest that PTR and DC present in rat thymic cultures belong to different cell lineages, and that they are, respectively, the in vitro equivalents of intrathymic macrophages and interdigitating cells.
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PMID:Rat thymic cultures: morphological and phenotypical characterization. 207 Nov 61


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