Biological chemistry Hoppe-Seyler最新文献_第4页

Determination of choline dehydrogenase activity along the rat nephron. 大鼠肾单位胆碱脱氢酶活性的测定。

Biological chemistry Hoppe-Seyler Pub Date : 1996-02-01 DOI: 10.1515/bchm3.1996.377.2.129

B Miller, H Schmid, T J Chen, M Schmolke, W G Guder

{"title":"Determination of choline dehydrogenase activity along the rat nephron.","authors":"B Miller, H Schmid, T J Chen, M Schmolke, W G Guder","doi":"10.1515/bchm3.1996.377.2.129","DOIUrl":"https://doi.org/10.1515/bchm3.1996.377.2.129","url":null,"abstract":"A radioenzymatic microassay was developed to quantitate choline dehydrogenase activity in single microdissected nephron segments. This enzyme is the rate limiting step in the biosynthesis of betaine, which serves as an intracellular osmoregulatory organic solute in mammalian kidney. The enzyme localized in renal mitochondrial inner membrane forms betaine aldehyde, which in the assay is converted to betaine by oxidative treatment. A histochemical procedure based on the formazan detection of tetranitroblue tetrazolium chloride was applied in parallel. The results show that activities in proximal convoluted and straight tubules are more than 5 times higher (21 to 25 pmol h-1 mm tubule-1) compared to distal nephron segments with no significant differences along the proximal tubule. Along the osmotic gradient from the outer medullary towards the papillary structures enzyme activities increased in ascending limbs of Henle's loop and collecting tubules. Collecting ducts showed two times higher activities than ascending loop segments when corrected for tubular cell volumes. The quantitative data were confirmed by the histochemical procedure. The results allow for the conclusion that betaine synthesis is sufficient to build up renal betaine, but cannot explain the distribution pattern of betaine along the corticopapillary axis. Additional mechanisms like intrarenal and tubular transport have to be postulated.","PeriodicalId":8963,"journal":{"name":"Biological chemistry Hoppe-Seyler","volume":"377 2","pages":"129-37"},"PeriodicalIF":0.0,"publicationDate":"1996-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/bchm3.1996.377.2.129","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19834269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15

Positive and negative regulatory regions in promoters of human glutathione transferase alpha genes. 人谷胱甘肽转移酶基因启动子的正调控区和负调控区。

Biological chemistry Hoppe-Seyler Pub Date : 1996-01-01 DOI: 10.1515/bchm3.1996.377.1.39

M Lorper, W A Schulz, F Morel, U Warskulat, H Sies

{"title":"Positive and negative regulatory regions in promoters of human glutathione transferase alpha genes.","authors":"M Lorper, W A Schulz, F Morel, U Warskulat, H Sies","doi":"10.1515/bchm3.1996.377.1.39","DOIUrl":"https://doi.org/10.1515/bchm3.1996.377.1.39","url":null,"abstract":"The human glutathione transferase (GST, EC 2.5.1.18) alpha class locus comprises several genes and pseudogenes. Genomic DNA encoding several human alpha-class-related genes and pseudogenes was cloned and characterized. Three distinct but highly similar 5'-flanking regions of GST alpha genes as well as a series of 5'-deletions were investigated for promoter activity by fusion to the luciferase reporter gene. Transient transfection of these luciferase constructs into human hepatoblastoma, kidney carcinoma, nephroblastoma or bladder carcinoma cells revealed that the promoters are active and contain both positive and negative regulatory regions that behave in a cell-type specific fashion. The 150 bp proximal promoter regions of the three sequences retained the same relative activities as the full length promoters. Two of them were equally active, whereas the third one showed only 20% of the activity of the two stronger promoters. Site-directed mutagenesis indicated that a conspicuous insertion of three nucleotides (TTT) in the weak promoter is not responsible for the different activities.","PeriodicalId":8963,"journal":{"name":"Biological chemistry Hoppe-Seyler","volume":"377 1","pages":"39-46"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/bchm3.1996.377.1.39","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19893216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 12

Characterization of phloretin-sensitive urea export from the perfused rat liver. 大鼠肝灌注后紫丁香醛敏感尿素输出特性的研究。

Biological chemistry Hoppe-Seyler Pub Date : 1996-01-01 DOI: 10.1515/bchm3.1996.377.1.25

S vom Dahl, D Haussinger

{"title":"Characterization of phloretin-sensitive urea export from the perfused rat liver.","authors":"S vom Dahl, D Haussinger","doi":"10.1515/bchm3.1996.377.1.25","DOIUrl":"https://doi.org/10.1515/bchm3.1996.377.1.25","url":null,"abstract":"In single pass perfused rat liver, rapid osmotic water shifts across the plasma membrane in response to hyperosmolar urea were followed by monitoring liver mass and transient concentrating or diluting effects on Na+ concentration in effluent perfusate. Sudden addition or removal of hyperosmolar urea (200mM, resulting in a step change of the perfusate osmolarity from 305 to 505 mosmol/l) had little effect on liver mass or Na+ activity in the effluent perfusate, suggesting that urea equilibrated at a rate similar to that of water across the liver plasma membrane. When, however, phloretin (0.2mM) was present, sudden addition (removal) of urea (200mM) induced within seconds a marked and transient decrease (increase) of both liver mass and effluent Na+ concentration, suggestive of transient osmotic water shifts out of/into the cells. Although to a lesser extent, comparable effects were induced when urea was added/removed in the presence of the phloretin-related phenol compounds 2,4,6-trihydroxyacetophenone (5mM) and 2,4,5-trihydroxybutyrophenone (5mM). Phloretin-induced inhibition of urea export from livers preloaded with [14C]urea was reversible, and no saturation of urea transport was found at concentrations up to 200mM. In contrast to [14C]urea transport, [3H]water transport across the plasma membrane was not affected by phloretin. The data indicate that urea export across the hepatocyte plasma membrane is almost as fast as water export. The urea transport mechanism is sensitive to phloretin and other phenol compounds, works with high capacity and is distinct from the water-transporting system. The regulation of this putative transport mechanism and its relevance for hepatic nitrogen metabolism remain to be established.","PeriodicalId":8963,"journal":{"name":"Biological chemistry Hoppe-Seyler","volume":"377 1","pages":"25-37"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/bchm3.1996.377.1.25","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19893215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Differential sensitivity of zinc finger transcription factors MTF-1, Sp1 and Krox-20 to CpG methylation of their binding sites. 锌指转录因子 MTF-1、Sp1 和 Krox-20 对其结合位点 CpG 甲基化的敏感性不同。

Biological chemistry Hoppe-Seyler Pub Date : 1996-01-01 DOI: 10.1515/bchm3.1996.377.1.47

F Radtke, M Hug, O Georgiev, K Matsuo, W Schaffner

{"title":"Differential sensitivity of zinc finger transcription factors MTF-1, Sp1 and Krox-20 to CpG methylation of their binding sites.","authors":"F Radtke, M Hug, O Georgiev, K Matsuo, W Schaffner","doi":"10.1515/bchm3.1996.377.1.47","DOIUrl":"10.1515/bchm3.1996.377.1.47","url":null,"abstract":"Cytosine methylation at CpG sites is often negatively correlated with mammalian gene activity. Many transcription factors whose DNA binding site contains one or more CpG dinucleotides are no longer able to efficiently bind DNA when the site is methylated. A notable exception is the zinc finger factor Sp1 which binds DNA and activates transcription even when its binding site is methylated. Here we show that two other zinc finger factors, MTF-1 and Krox-20, can also bind to CpG methylated sites. MTF-1 regulates metallothionein gene transcription by binding to a number of metal responsive elements (MREs), and Krox-20 regulates Hox genes during hindbrain segmentation. However, a refined analysis of MTF-1/MRE binding shows that methylation is not tolerated at every binding site: the highest affinity site in the mouse metallothionein I gene, MREd, is unaffected by methylation, while two other MRE sites with CpGs at different positions are rendered partially or completely nonfunctional by methylation. Both methylation sensitive and insensitive factors/binding sites are likely to determine the developmental expression pattern of a gene.","PeriodicalId":8963,"journal":{"name":"Biological chemistry Hoppe-Seyler","volume":"377 1","pages":"47-56"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/bchm3.1996.377.1.47","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19893217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 33

Minimally modified oligonucleotides - combination of end-capping and pyrimidine-protection. 最小修饰寡核苷酸——端盖和嘧啶保护的组合。

Biological chemistry Hoppe-Seyler Pub Date : 1996-01-01 DOI: 10.1515/bchm3.1996.377.1.67

A Peyman, E Uhlmann

引用次数: 46

The biostructural pathology of the serpins: critical function of sheet opening mechanism. 蛇形蛋白的生物结构病理学:开片机制的关键功能。

Biological chemistry Hoppe-Seyler Pub Date : 1996-01-01 DOI: 10.1515/bchm3.1996.377.1.1

R W Carrell, P E Stein

{"title":"The biostructural pathology of the serpins: critical function of sheet opening mechanism.","authors":"R W Carrell, P E Stein","doi":"10.1515/bchm3.1996.377.1.1","DOIUrl":"https://doi.org/10.1515/bchm3.1996.377.1.1","url":null,"abstract":"The serpins illustrate the way in which the study of a protein family as a whole can clarify the functions of its individual members. Although the individual serpins have become remarkably diversified by evolution they all share a common structural pathology. We have previously shown how plotting of the dysfunctional natural mutations of the serpins on a template structure defines the domains controlling the mobility of the reactive centre loop of the molecule. Here we compare these natural mutations with reciprocal mutations in recombinants that restore the inhibitory stability of a labile member of the family, plasminogen activator inhibitor-1 (PAI-1). The combined results emphasise the critical part played by residues involved in the sliding movement that opens the A-sheet to allow reactive loop insertion. It is concluded that changes in these residues provide the prime explanation for the ready conversion of PAI-1 to the inactive latent state. The consistency of the overall results gives confidence in predicting the likely consequences of mutations in individual serpins. In particular the two common polymorphic mutations present in human angiotensinogen are likely to affect molecular stability and hence may be contributory factors to the observed association with vascular disease.","PeriodicalId":8963,"journal":{"name":"Biological chemistry Hoppe-Seyler","volume":"377 1","pages":"1-17"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/bchm3.1996.377.1.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19893213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 94

Anisoosmotic regulation of hepatic gene expression. 肝脏基因表达的各向同性调控。

Biological chemistry Hoppe-Seyler Pub Date : 1996-01-01 DOI: 10.1515/bchm3.1996.377.1.57

U Warskulat, W Newsome, B Noe, B Stoll, D Haussinger

{"title":"Anisoosmotic regulation of hepatic gene expression.","authors":"U Warskulat, W Newsome, B Noe, B Stoll, D Haussinger","doi":"10.1515/bchm3.1996.377.1.57","DOIUrl":"https://doi.org/10.1515/bchm3.1996.377.1.57","url":null,"abstract":"The effect of anisoosmolarity on the abundance of various mRNA species was examined in perfused rat liver and H4IIE rat hepatoma cells. Hyperosmotic exposure (385 mosmol/l) of isolated rat livers increased mRNA levels for tyrosine aminotransferase (TAT) by 246% and those for phosphoenolpyruvate carboxykinase (PEPCK) by 186%, whereas hypoosmotic exposure (225 mosmol/l) decreased their levels to 43% and 42%, respectively. mRNA levels for fructose-1,6-bisphosphatase (FBP), argininosuccinate lyase (ASL), argininosuccinate synthetase (ASS), glutamine synthetase (GS), glutaminase (GA) and glucokinase (GK) were largely unaffected. In H4IIE cells the modulation of TAT and PEPCK mRNA levels by anisoosmotic exposure was similar to that found in perfused rat liver. ASL and glutaminase mRNA levels were influenced in an opposite manner. The effects of anisoosmolarity on PEPCK mRNA levels in H4IIE cells were largely abolished in the presence of the protein kinase inhibitors H-7, H-89 and HA-1004. Other protein kinase inhibitors such as Go-6850, KN-62, Rp-8-CPT-cAMPS, rapamycin, wortmannin, genistein or herbimycin did not prevent the osmosensitivity of PEPCK mRNA levels. Also pertussis and cholera toxin, vanadate and colchicine did not affect the osmosensitivity of PEPCK mRNA levels. The data suggest that anisoosmotic exposure acts on the levels of some but not all mRNA species and that this action may involve changes in protein phosphorylation. They further indicate that the recently identified osmosensitive signal transduction pathway which involves a G-protein and tyrosine kinase dependent activation of mitogen-activated protein kinases is apparently not involved in the osmoregulation of PEPCK mRNA levels.","PeriodicalId":8963,"journal":{"name":"Biological chemistry Hoppe-Seyler","volume":"377 1","pages":"57-65"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/bchm3.1996.377.1.57","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19893218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 30

Biochemistry, regulation and potential function of kallistatin. 卡利司他汀的生物化学、调控及潜在功能。

Biological chemistry Hoppe-Seyler Pub Date : 1995-12-01

J Chao, L Chao

{"title":"Biochemistry, regulation and potential function of kallistatin.","authors":"J Chao, L Chao","doi":"","DOIUrl":"","url":null,"abstract":"Components of the tissue kallikrein-kinin system include tissue kallikrein, kallistatin (kallikrein-binding protein), kininogen, kinin, bradykinin B1 and B2 receptors, and kininases. Tissue kallikrein is a serine proteinase which is capable of cleaving kininogen substrate to release the vasoactive kinin peptide. The binding of kinin to its specific receptor at target organs can produce a wide spectrum of biological effects. Kinin generation is primarily determined by the activity and availability of kallikrein since the level of kininogen is not a rate-limiting factor. Kallikrein levels are controlled by its rate of synthesis, activation, inactivation and clearance. The synthesis of tissue kallikrein is regulated transcriptionally, and its activity is regulated through post-translational processing and inactivation by inhibitors. Kallistatin is a newly discovered serine proteinase inhibitor (serpin) which forms a specific and covalently-linked complex with tissue kallikrein. Kallistatin may regulate tissue kallikrein's activity, bioavailability and clearance rate at the post-translational level. The major site of kallistatin synthesis is the liver with lower expression levels in the pancreas and kidney. Unlike many other serpins which are only present in the plasma, kallistatin is found in various tissues, cells and bodily fluids. The fact that both tissue kallikrein and kallistatin are widely distributed in tissues suggests kallistatin's role as a potential regulator of kallikrein outside the circulation. Protein purification and molecular cloning techniques have been used to study the structure, regulation and function of the components of the kallikrein-kinin system and for exploring their roles in ion transport, inflammation and blood pressure regulation. Considerable progress has been made in recent years to achieve these goals. This article provides an overview of the biochemical properties and potential physiological and pathophysiological roles of kallistatin.","PeriodicalId":8963,"journal":{"name":"Biological chemistry Hoppe-Seyler","volume":"376 12","pages":"705-13"},"PeriodicalIF":0.0,"publicationDate":"1995-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20027202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The gradual reduction of viroid levels in hop mericlones following heat therapy: a possible role for a nuclease degrading dsRNA. 热治疗后啤酒花美克隆中类病毒水平的逐渐降低:核酸酶降解dsRNA的可能作用。

Biological chemistry Hoppe-Seyler Pub Date : 1995-12-01 DOI: 10.1515/bchm3.1995.376.12.715

J Matousek, L Trnĕná, P Svoboda, P Oriniaková, C P Lichtenstein

{"title":"The gradual reduction of viroid levels in hop mericlones following heat therapy: a possible role for a nuclease degrading dsRNA.","authors":"J Matousek, L Trnĕná, P Svoboda, P Oriniaková, C P Lichtenstein","doi":"10.1515/bchm3.1995.376.12.715","DOIUrl":"https://doi.org/10.1515/bchm3.1995.376.12.715","url":null,"abstract":"A high concentration of hop latent viroid (HLVd) was detected in infected mericlones of Osvald's hops grown in vitro. This concentration was about 8-fold higher than in leaves of young, field-grown plants, reaching about 30 pg/mg of fresh mass. Treatment of these in vitro-grown plants at high temperature (35 degrees C) for two weeks lead to a dramatic (about 70-90%) decrease of HLVd content. More detailed investigations performed with mericlone 6147 of Osvald 31 showed that HLVd levels decrease gradually during subsequent cycles of heat treatment. A nuclease activity capable of cleaving HLVd and fully double-stranded RNA was shown to increase significantly in hop tissues during thermotherapy cycles, or after the heat shock. The nuclease activity was found to have similar properties to those extracted earlier from tobacco anthers. This enzyme resembles a sugar-unspecific nuclease which has a maximum activity at pH 5.5. Analysis of the activity with viroid and dsRNA showed that both, endo- and exonucleolytic activities were attributable to the enzyme. A strong tissue-specific gradient of viroid (the lowest level in stem apex and the highest level in roots) was observed in young plants, showing a negative correlation with the dsRNAse activity. In senescent plants, the highest viroid concentration was observed in maturated cones and in upper stems. High nuclease activity in the upper stem tissue suggests that viroid RNA must be protected in this tissue against degradation.","PeriodicalId":8963,"journal":{"name":"Biological chemistry Hoppe-Seyler","volume":"376 12","pages":"715-21"},"PeriodicalIF":0.0,"publicationDate":"1995-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/bchm3.1995.376.12.715","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20027203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 29

New data on content and distribution of gangliosides in human milk. 人乳中神经节苷类含量和分布的新数据。

Biological chemistry Hoppe-Seyler Pub Date : 1995-12-01 DOI: 10.1515/bchm3.1995.376.12.723

R Rueda, R Puente, P Hueso, J Maldonado, A Gil

引用次数: 56