Enzyme & protein最新文献

Regulation of protein kinase C: a tale of lipids and proteins. 蛋白激酶C的调节:脂质和蛋白质的故事。

Enzyme & protein Pub Date : 1996-01-01 DOI: 10.1159/000468635

A F Quest

引用次数: 56

Proteolytic enzymes in cancer invasion. Introduction. 蛋白水解酶在癌症侵袭中的作用。介绍。

Enzyme & protein Pub Date : 1996-01-01

L Ossowski, R Mira y Lopez

引用次数: 0

Role of reactive oxygen and argininosuccinate in guanidinosuccinate synthesis in isolated rat hepatocytes. 活性氧和精氨酸琥珀酸盐在离体大鼠肝细胞中胍基琥珀酸盐合成中的作用。

Enzyme & protein Pub Date : 1996-01-01 DOI: 10.1159/000468630

K Aoyagi, S Nagase, M Gotoh, K Akiyama, M Satoh, A Hirayama, A Koyama

{"title":"Role of reactive oxygen and argininosuccinate in guanidinosuccinate synthesis in isolated rat hepatocytes.","authors":"K Aoyagi, S Nagase, M Gotoh, K Akiyama, M Satoh, A Hirayama, A Koyama","doi":"10.1159/000468630","DOIUrl":"https://doi.org/10.1159/000468630","url":null,"abstract":"The synthesis of guanidinosuccinic acid (GSA) increases in uremics, and GSA is implicated as a uremic toxin. The GSA synthesis increases roughly in proportion to the serum urea level that increases in patients with renal failure. Urea is a specific inhibitor of argininosuccinase, the fourth urea cycle enzyme, and might lead to the increase of argininosuccinate (ASA). We found that GSA is formed from ASA by reactive oxygen species in vitro. In this paper, we investigated GSA synthesis from ASA in isolated rat hepatocytes and the effect of reactive oxygen species on this synthesis. When isolated rat hepatocytes were incubated with 5 mmol/l ASA, GSA was formed linearly with time up to 6 h (16 nmol/g wet liver/6 h). GSA was formed depending on the ASA concentration up to 10 mmol/l. Dimethylsulfoxide, a hydroxyl radical scavenger, inhibited GSA synthesis by 65%. GSA was actively formed when the hepatocytes were incubated with 32 mmol/l urea. The GSA formation in the presence of urea was also inhibited by dimethylsulfoxide, although the inhibition was less marked. FeCl2, that increases the hydroxyl radical generation, increased GSA synthesis. These results indicate that GSA is formed from ASA in isolated hepatocytes. The results also suggest that reactive oxygen species are important for GSA synthesis in the cells.","PeriodicalId":11854,"journal":{"name":"Enzyme & protein","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000468630","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19988183","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

Isozymes of superoxide dismutase from Aloe vera. 芦荟超氧化物歧化酶同工酶。

Enzyme & protein Pub Date : 1996-01-01 DOI: 10.1159/000468631

F Sabeh, T Wright, S J Norton

引用次数: 38

What structure and function of avian plasminogen activator and matrix metalloproteinase-2 reveal about their counterpart mammalian enzymes, their regulation and their role in tumor invasion. 禽纤溶酶原激活物和基质金属蛋白酶-2的结构和功能揭示了它们在哺乳动物中的对应酶、调控及其在肿瘤侵袭中的作用。

Enzyme & protein Pub Date : 1996-01-01 DOI: 10.1159/000468615

D S Alexander, R T Aimes, J P Quigley

{"title":"What structure and function of avian plasminogen activator and matrix metalloproteinase-2 reveal about their counterpart mammalian enzymes, their regulation and their role in tumor invasion.","authors":"D S Alexander, R T Aimes, J P Quigley","doi":"10.1159/000468615","DOIUrl":"https://doi.org/10.1159/000468615","url":null,"abstract":"Rous sarcoma virus-transformed chick embryo fibroblasts (RSVCEF) constitute a well-characterized model system for oncogenic transformation, matrix degradation, and cancer invasion. As RSVCEF cultures employ both serine protease and metalloprotease cascades in the process of matrix degradation, they have contributed significantly to understanding the nature and regulation of these molecules involved in invasive cell behavior. RSVCEF produce elevated levels of a matrix metalloprotease-2 (MMP-2) whose hemopexin domain differs from mammalian MMP-2. The majority of MMP-2 produced by RSVCEF is present in a TIMP-free form which enhances its activation, catalytic activity and substrate specificity and therefore its matrix-degrading ability. RSVCEFs also exhibit high levels of urokinase-type plasminogen activator (uPA), which is found in active form in their conditioned medium in complete absence of plasminogen. Recombinantly expressed avian uPA is also in active form, while an active-site mutant of the same maintains its zymogen form, indicating the mechanism of activation of chicken uPA is autocatalytic. A domain and sequence comparison between chicken and human uPA attempts to identify motifs potentially responsible for the zymogen instability of avian uPA and its capability to autoactivate.","PeriodicalId":11854,"journal":{"name":"Enzyme & protein","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000468615","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19766944","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: 9

MMP-2: expression, activation and inhibition. MMP-2:表达、激活和抑制。

Enzyme & protein Pub Date : 1996-01-01 DOI: 10.1159/000468613

M L Corcoran, R E Hewitt, D E Kleiner, W G Stetler-Stevenson

引用次数: 206

Bryostatin 1 induces ubiquitin COOH-terminal hydrolase in acute lymphoblastic leukemia cells. 苔藓虫素1诱导急性淋巴细胞白血病细胞泛素cooh末端水解酶。

Enzyme & protein Pub Date : 1996-01-01 DOI: 10.1159/000468636

R M Mohammad, A Maki, G R Pettit, A M al-Katib

{"title":"Bryostatin 1 induces ubiquitin COOH-terminal hydrolase in acute lymphoblastic leukemia cells.","authors":"R M Mohammad, A Maki, G R Pettit, A M al-Katib","doi":"10.1159/000468636","DOIUrl":"https://doi.org/10.1159/000468636","url":null,"abstract":"It has been previously reported that Bryostatin 1 (Bryo1) induces differentiation of the human acute lymphoblastic leukemia (ALL) cell line, Reh, to a monocytoid B-cell stage. In this study we demonstrate that a novel protein, ubiquitin COOH-terminal hydrolase (UCH-L1), is associated with this differentiation. Reh cells were treated with 200 nmol/l of Bryo1 for 72 h and analyzed for changes in morphology, surface immunophenotype, acid phosphatase and terminal deoxynucleotidyl transferase. Protein patterns of the parent and differentiated cells, by two-dimensional polyacrylamide gel electrophoresis (2D PAGE), were studied. Bryo1-treated cells expressed morphologic, phenotypic and enzymatic features of the monocytoid B-cell stage. The UCH-L1 enzyme (MW-pl 34-5.3) was detected by 2 D PAGE in the differentiated, but not in parent cells. The presence of UCH-L1 in the Bryo1-treated cells was further confirmed by immunoblotting of 2 D PAGE using UCH-L1 polyclonal antibody. Ubiquitin expression was studied in parent and Bryo1-treated cells and was compared with 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated cells. Both agents, TPA and Bryo1, increased the level of ubiquitin expression as detected by flow cytometry. Sodium borohydride, an inhibitor of UCH-L1, inhibited the Bryo1-induced differentiating effect on Reh cells. To date, the mechanism by which Bryo1, exerts its B-cell differentiating effect is not fully understood. This study shows that UCH-L1 expression may play a major role in Bryo1-induced differentiation in pre-B-ALL.","PeriodicalId":11854,"journal":{"name":"Enzyme & protein","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000468636","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20195753","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: 10

Steady-state kinetics of Thr35 and Thr39 mutants in human adenylate kinase by site-directed mutagenesis. 位点定向诱变人腺苷酸激酶Thr35和Thr39突变体的稳态动力学。

Enzyme & protein Pub Date : 1996-01-01 DOI: 10.1159/000468640

T Ayabe, H Takenaka, T Onitsuka, K Shibata, O Takenaka, S Uesugi, M Hamada

引用次数: 0

Plasminogen activators and matrix metalloproteinases in angiogenesis. 血管生成中的纤溶酶原激活剂和基质金属蛋白酶。

Enzyme & protein Pub Date : 1996-01-01 DOI: 10.1159/000468621

P Mignatti, D B Rifkin

{"title":"Plasminogen activators and matrix metalloproteinases in angiogenesis.","authors":"P Mignatti, D B Rifkin","doi":"10.1159/000468621","DOIUrl":"https://doi.org/10.1159/000468621","url":null,"abstract":"In the initial stages of capillary formation (angiogenesis) microvascular endothelial cells of preexisting blood vessels locally degrade the underlying basal lamina and invade into the stroma of the tissue to be vascularized. A consistent body of experimental evidence has shown that this process requires a wide array of dedradative enzymes. Components of the plasminogen activator (PA)-plasmin system and of the matrix metalloproteinase (MMP) family play important roles. PAs trigger a proteinase cascade that results is the generation of high local concentrations of plasmin and active MMPs. This increase in proteolytic activity has three major consequences: it permits endothelial cell degradation and invasion of the vessel basal lamina, generates extracellular matrix (ECM) degradation products that are chemotactic for endothelial cells, and activates and mobilizes growth factors localized in the ECM. In addition, urokinase-type PA modulates some endothelial cell functions, including proliferation and migration, with a mechanism independent of proteolytic activity. PA and MMP activities are modulated in endothelial cells by complex mechanisms, including transcriptional regulation by a variety of growth factors and cytokines with angiogenic activity, extracellular control of the proteolytic activities by tissue inhibitors, and interaction with binding sites on the cell membrane and ECM.","PeriodicalId":11854,"journal":{"name":"Enzyme & protein","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000468621","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19766950","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: 342

Relationship between adipose polyamine concentrations and triacylglycerol synthetic enzymes in lean and obese Zucker rats. 胖瘦Zucker大鼠脂肪多胺浓度与甘油三酯合成酶的关系

Enzyme & protein Pub Date : 1996-01-01 DOI: 10.1159/000468632

S C Jamdar, W F Cao, E Samaniego

{"title":"Relationship between adipose polyamine concentrations and triacylglycerol synthetic enzymes in lean and obese Zucker rats.","authors":"S C Jamdar, W F Cao, E Samaniego","doi":"10.1159/000468632","DOIUrl":"https://doi.org/10.1159/000468632","url":null,"abstract":"Previous studies from our laboratory demonstrate that polyamines, namely spermine and spermidine, stimulate adipose triacylglycerol formation from the sn-glycerol-3-phosphate pathway by activation of several enzymes from this pathway, including sn-glycerol-3-phosphate acyltransferase, Mg(2+)-dependent phosphatidate phosphohydrolase and diacylglycerol acyltransferase. Since obesity in Zucker rats was associated with increased accumulation of adipocyte triacylglycerols, we have examined the relationship between changes in the activities of various triacylglycerol synthetic enzymes and the endogenous concentrations of spermine and spermidine in the adipose tissues from lean and obese animals. As compared with lean rats, the adipocytes from obese rats showed a 4-fold rise in the concentration of spermine and spermidine which was accompanied by 4- to 14-fold increases in the activities of various triacylglycerol synthetic enzymes, including Mg(2+)-dependent phosphatidate phosphohydrolase. These studies suggest that obesity in Zucker rats is associated with the activation of various adipose triacylglycerol synthetic enzymes resulting from increased concentrations of endogenous spermine and spermidine.","PeriodicalId":11854,"journal":{"name":"Enzyme & protein","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000468632","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19988185","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: 16