Enzyme & protein最新文献_第7页

Synthetic inhibitors of the multicatalytic proteinase complex (proteasome). 合成多催化蛋白酶复合物(蛋白酶体)抑制剂。

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468688

S Wilk, M E Figueiredo-Pereira

引用次数: 48

Proteasomes. Multicatalytic proteinase complexes. 水解酶。多催化蛋白酶复合物。

Enzyme & protein Pub Date : 1993-01-01

S Wilk

引用次数: 0

Studies on the yeast proteasome uncover its basic structural features and multiple in vivo functions. 酵母蛋白酶体的研究揭示了其基本结构特征和多种体内功能。

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468678

W Hilt, W Heinemeyer, D H Wolf

引用次数: 34

Subunit stoichiometry of human proteasomes. 人蛋白酶体的亚基化学计量学。

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468682

K B Hendil, K G Welinder, D Pedersen, W Uerkvitz, P Kristensen

引用次数: 12

Modulation of the multicatalytic proteinase complex by lipids, interconversion and proteolytic processing. 脂质、相互转化和蛋白水解过程对多催化蛋白酶复合物的调节。

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468686

P Arizti, J Arribas, J G Castaño

引用次数: 15

Measurement of totally activated pyruvate dehydrogenase complex activity in human muscle: evaluation of a useful assay. 测定人体肌肉中完全活化的丙酮酸脱氢酶复合体的活性:评价一种有用的测定方法。

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468654

W Sperl, J M Trijbels, W Ruitenbeek, H L van Laack, A J Janssen, C M Kerkhof, R C Sengers

{"title":"Measurement of totally activated pyruvate dehydrogenase complex activity in human muscle: evaluation of a useful assay.","authors":"W Sperl, J M Trijbels, W Ruitenbeek, H L van Laack, A J Janssen, C M Kerkhof, R C Sengers","doi":"10.1159/000468654","DOIUrl":"https://doi.org/10.1159/000468654","url":null,"abstract":"A sensitive radiochemical method for the determination of the pyruvate dehydrogenase complex (PDHC) activity in skeletal muscle tissue, based on the decarboxylation of [1-14C]-pyruvate to 14CO2, is described. Measurements can be carried out either in muscle homogenate or in 600-g supernatant, both obtainable from a small muscle biopsy specimen (20 mg). In addition to NAD+, thiamine pyrophosphate and coenzyme A in the incubation mixture, a preparation of NADH:cytochrome c reductase (NADHCR) together with cytochrome c has a stimulating effect on the PDHC activity. NADHCR constitutes an oxidation system for NADH to prevent feedback inhibition. Addition of L-carnitine also results in stimulation of PDHC by trapping the produced acetyl-CoA as acetylcarnitine. Special care for radioactive pyruvate, with freeze drying and storage at -20 degrees C under nitrogen, and determination of the purity during every PDHC assay, is required. In the presented assay a Km value of 0.084 mmol/l was found for pyruvate. Nonsigmoidal kinetics was found with a Hill coefficient of 1.63. With the described method, a totally Mg2+,Ca(2+)-stimulated PDHC activity is measured. Addition of a purified specific pyruvate dehydrogenase phosphatase did not yield a higher PDHC activity. Finally, comparison of total PDHC activity with [1-14C]-pyruvate oxidation rates, both measured in the supernatant prepared from fresh muscle, shows an equimolar correlation, indicating that total PDHC activity is rate limiting in the assay for the pyruvate oxidation rate. Neonatal muscle exhibits five to ten times lower PDHC activities and pyruvate oxidation rates than controls (age > 3 years).","PeriodicalId":11854,"journal":{"name":"Enzyme & protein","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000468654","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19008608","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

Serum enzyme activities in full-term asphyxiated and healthy newborns: enzyme kinetics during the first 144 hours of life. 足月窒息和健康新生儿血清酶活性:生命最初144小时的酶动力学

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468672

G M Lackmann, U Töllner, R Mader

{"title":"Serum enzyme activities in full-term asphyxiated and healthy newborns: enzyme kinetics during the first 144 hours of life.","authors":"G M Lackmann, U Töllner, R Mader","doi":"10.1159/000468672","DOIUrl":"https://doi.org/10.1159/000468672","url":null,"abstract":"Little is known about the kinetics of most serum enzymes during the first hours of life, and even less about the effect on such enzyme activities of perinatal hypoxia-ischaemia. It was the aim of the present study to evaluate the serum kinetics of seven differently located cell enzymes in healthy and asphyxiated newborns during the 1st week of life. The serum activities of cytoplasmic and mitochondrial [aspartate aminotransferase (ASAT), creatine kinase (CK), glutamate dehydrogenase (GLDH), lactate dehydrogenase (LDH), and hydroxybutyrate dehydrogenase (HBDH)] and membrane-bound (gamma-glutamyl-transferase and leucine arylaminidase) enzymes were prospectively measured in full-term asphyxiated (n = 49) and healthy (n = 87) newborns during the first 144 h of life. The blood samples were taken serially at five fixed times: 0 (cord), 12, 24, 72, and 144 h postpartum. The asphyxiated newborns had significantly increased serum activities of ASAT, LDH, and HBDH up to 72 h postpartum, whereas healthy newborns showed higher CK and GLDH activities. Only the activities of ASAT, LDH, and HBDH seemed to depend on the oxygen supply of the fetus or newborn. If other causes of increased serum enzyme activities, e.g. liver diseases, haemolytic disorders, tumours, or inborn errors of metabolism, are excluded, elevated serum activities of ASAT, LDH, and HBDH should draw one's attention to a perinatal hypoxic-ischaemic insult of the newborn.","PeriodicalId":11854,"journal":{"name":"Enzyme & protein","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000468672","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18913616","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: 48

Purification and characterization of low molecular weight fibrinolytic/hemorrhagic enzymes from snake (Bothrops jararaca) venom. 蛇(Bothrops jararaca)毒液中低分子量纤溶/出血酶的纯化及特性研究。

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468668

M Maruyama, M Tanigawa, M Sugiki, E Yoshida, H Mihara

{"title":"Purification and characterization of low molecular weight fibrinolytic/hemorrhagic enzymes from snake (Bothrops jararaca) venom.","authors":"M Maruyama, M Tanigawa, M Sugiki, E Yoshida, H Mihara","doi":"10.1159/000468668","DOIUrl":"https://doi.org/10.1159/000468668","url":null,"abstract":"Two low molecular weight fibrinolytic/hemorrhagic enzymes, jararafibrase III and jararafibrase IV, were purified from Bothrops jararaca venom using a fast protein liquid chromatography system. The purified jararafibrase III and jararafibrase IV were single chain proteins with molecular weights of 20,400 +/- 500 and 21,200 +/- 400, respectively, by SDS-PAGE. The isoelectric points of jararafibrase III and jararafibrase IV were 9.4 and 6.9, respectively. The activity of the enzyme was inhibited by 1,10-phenanthroline and EDTA, suggesting that both enzymes were metalloproteinases. The specific fibrinolytic activities of jararafibrase III and jararafibrase IV were 7.5 +/- 0.4 and 6.5 +/- 1.6 units/mg protein, respectively. The enzymes induced local hemorrhage in the skin of rats. The minimal hemorrhagic doses of jararafibrase III and IV were 31.0 and 34.0 micrograms/rat, respectively. The enzymes displayed broad substrate specificities like the previously purified jararafibrases I and II. Jararabrases III and IV degraded type-IV collagen, gelatin, laminin and fibronectin into smaller fragments. The specific activities of jararafibrase III for type-IV collagen and gelatin were 7.6 +/- 0.3 and 43 +/- 11 units/mg protein, respectively. The specific activities of jararafibrase IV for type IV-collagen and gelatin were 16.5 +/- 1.2 and 112 +/- 9 units/mg protein, respectively.","PeriodicalId":11854,"journal":{"name":"Enzyme & protein","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000468668","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19080626","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

Characterization of mouse proteasome subunit MC3 and identification of proteasome subtypes with different cleavage characteristics. Proteasome subunits, proteasome subpopulations. 小鼠蛋白酶体亚基MC3的鉴定及不同裂解特性的蛋白酶体亚型的鉴定。蛋白酶体亚基，蛋白酶体亚群。

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468691

A Seelig, B Boes, P M Kloetzel

{"title":"Characterization of mouse proteasome subunit MC3 and identification of proteasome subtypes with different cleavage characteristics. Proteasome subunits, proteasome subpopulations.","authors":"A Seelig, B Boes, P M Kloetzel","doi":"10.1159/000468691","DOIUrl":"https://doi.org/10.1159/000468691","url":null,"abstract":"We have isolated and characterized a cDNA encoding the mouse proteasome subunit MC3 and identified four proteasome subtypes which differ in their peptide-hydrolyzing and polypeptide-cleavage properties. Immunoblotting data show that the 25-kD MC3 subunit is a constitutive proteasome subunit which exists in several isoforms. In addition, by immunoprecipitation of proteasomes with AbMC3, a subset of enzyme complexes could be recognized which differ in their relative subunit composition from the bulk of proteasomes. Using DEAE-column chromatography we identified three different proteasome subtypes in sol-80 mouse liver extracts and, by Trition X-100 extraction, a distinct membrane-bound subtype. The four proteasome subtypes are shown to differ in their trypsin- and chymotrypsin-like hydrolyzing activities as well as in their ability to cleave a 25mer polypeptide substrate derived from the MCMV IE pp89. Our data indicate that the enzymatic properties observed for the total proteasome population may be the summary of cleavage properties of different types of proteasome complexes.","PeriodicalId":11854,"journal":{"name":"Enzyme & protein","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000468691","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18698605","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: 21

Characterization of the alkaline phosphatase expressed on the surface of a Hodgkin's lymphoma cell line. 碱性磷酸酶在霍奇金淋巴瘤细胞系表面表达的特性。

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468660

L Belland, L Visser, S Poppema, R A Stinson

{"title":"Characterization of the alkaline phosphatase expressed on the surface of a Hodgkin's lymphoma cell line.","authors":"L Belland, L Visser, S Poppema, R A Stinson","doi":"10.1159/000468660","DOIUrl":"https://doi.org/10.1159/000468660","url":null,"abstract":"Alkaline phosphatase solubilized from a human Hodgkin's lymphoma cell line (L428) was compared with purified amphiphilic and hydrophilic forms of the enzyme from human liver, and with the enzyme solubilized from a cultured osteosarcoma cell line (Saos-2). Purified hydrophilic alkaline phosphatases from human placenta and intestine were also compared in some experiments. Alkaline phosphatase was released from the plasma membrane of intact lymphocytes by phosphatidylinositol phospholipase C and thus is anchored to the outside of the plasma membrane by covalently attached phosphatidylinositol. Enzyme released in this way was hydrophilic and that solubilized with Triton X-100 was amphiphilic, as assessed by adsorption to octyl-Sepharose. Lymphocyte alkaline phosphatase, when released from the membrane by phosphatidylinositol phospholipase C or solubilized by Triton X-100, had apparent M(r) values on gradient gel electrophoresis of 227 and 494 kDa, respectively. These values were consistently higher than equivalent ones obtained with enzymes purified from human liver, but were similar to those of cultured osteosarcoma cells. Isoenzyme-specific inhibitors of alkaline phosphatase showed similar patterns of inhibition between the enzyme from L428 cells and the tissue-nonspecific (liver/kidney/bone) isoenzyme from human liver. Heat stabilities were similar for the enzymes from L428 and Saos-2 (bone isoform) cell lines, but differed significantly from those of liver, intestine and placenta. We conclude that the alkaline phosphatase expressed in this lymphoma cell line (L428) has properties that most closely resemble those of the tissue-nonspecific isoenzyme found normally in osteoblasts of bone (bone isoform).","PeriodicalId":11854,"journal":{"name":"Enzyme & protein","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000468660","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19183598","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: 2