Enzyme & protein最新文献_第8页

Phosphorylation and ubiquitination of the 26S proteasome complex. 26S蛋白酶体复合物的磷酸化和泛素化。

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468690

J D Etlinger, S X Li, G G Guo, N Li

引用次数: 17

Role of proteasomes in antigen presentation. 蛋白酶体在抗原呈递中的作用。

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468693

M Gaczynska, K L Rock, A L Goldberg

{"title":"Role of proteasomes in antigen presentation.","authors":"M Gaczynska, K L Rock, A L Goldberg","doi":"10.1159/000468693","DOIUrl":"https://doi.org/10.1159/000468693","url":null,"abstract":"Recent studies have demonstrated that the proteasome, in addition to functioning in the complete degradation of cell proteins, is the source of most antigenic peptides presented to the immune system on major histocompatibility complex (MHC)-class I molecules. In this process, intracellular and viral proteins are degraded in the cytosol to 8- to 9-amino acid fragments, which are then transported into the endoplasmic reticulum, where they become associated with MHC-class I molecules and are thus delivered to the cell surface. A variety of evidence has shown that the proteasome and ATP-ubiquitin-dependent pathway are critical in this process: (1) In cells, selective inhibitors of proteasome function inhibit the bulk of protein degradation and thus prevent the generation of peptides necessary for class I presentation and the appearance of MHC on the cell surface. (2) Mutations that block ubiquitin conjugation prevent the generation of an antigenic peptide. (3) Modifications that lead to rapid degradation of a protein by the ubiquitin pathway enhance antigen presentation. (4) gamma-Interferon (gamma-IFN) induces new proteasome subunits, LMP2 and LMP7, encoded in the MHC region that are incorporated in place of constitutive proteasome subunits. Their incorporation does not affect rates of protein breakdown but causes changes in peptidase activities, i.e. they increase rates of cleavage after basic and hydrophobic residues and decrease cleavage after acidic residues. Transfections of cells with LMP2 or LMP7 cause similar changes in these peptidase activities as are caused by gamma-IFN. These modifications in peptidase activities should enhance the production of those types of peptides which are preferentially transported into endoplasmic reticulum and selectively bound to MHC-class I molecules.","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/10.1159/000468693","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18698607","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: 51

Glucose-6-phosphate dehydrogenase nucleotide 1311 polymorphism in central Italy (Marche Region). 意大利中部(马尔凯地区)葡萄糖-6-磷酸脱氢酶核苷酸1311多态性。

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468652

A Ruzzo, P Ninfali, M Magnani

引用次数: 5

Molecular cloning and sequence analysis of the cDNA for human mitochondrial short-chain enoyl-CoA hydratase. 人线粒体短链烯酰辅酶a水合酶cDNA的克隆及序列分析。

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468650

M Kanazawa, A Ohtake, H Abe, S Yamamoto, Y Satoh, M Takayanagi, H Niimi, M Mori, T Hashimoto

{"title":"Molecular cloning and sequence analysis of the cDNA for human mitochondrial short-chain enoyl-CoA hydratase.","authors":"M Kanazawa, A Ohtake, H Abe, S Yamamoto, Y Satoh, M Takayanagi, H Niimi, M Mori, T Hashimoto","doi":"10.1159/000468650","DOIUrl":"https://doi.org/10.1159/000468650","url":null,"abstract":"Short chain enoyl-CoA hydratase (SCEH) catalyzes the second step of the mitochondrial fatty acid beta-oxidation spiral. We isolated cDNA clones for human SCEH to facilitate investigation of the enzyme structure of the gene and to examine the genetic background of Reye's syndrome and sudden infant death. Oligo(dT)-primed and random primed human liver cDNA libraries in lambda gt11 were screened using the entire sequence of the rat SCEH cDNA as a probe. Three positive clones covered the full-length cDNA sequence with an open reading frame encoding a precursor polypeptide of 290 amino acid residues, and deduced relative molecular mass (31,280) with a putative N-terminal presequence of 29 residues, a 5'-untranslated sequence of 21 bp and a 3'-untranslated sequence of 391 bp. Comparison with the rat SCEH cDNA showed that the deduced amino acid sequence of the human SCEH precursor is 84% identical to that of the rat enzyme precursor. Northern blot analysis gave a single mRNA species of 1.6 kb in the human liver, fibroblast and muscle.","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/10.1159/000468650","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19008609","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: 35

11-beta-Hydroxysteroid dehydrogenase of rat lung: enzyme kinetic, oxidase-reductase ratio, electrolyte and trace element dependence. 大鼠肺11- β -羟基类固醇脱氢酶:酶动力学、氧化酶-还原酶比值、电解质及微量元素依赖性。

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468661

S Hundertmark, V Ragosch, B Schein, H Bühler, M Fromm, U Lorenz, H K Weitzel

{"title":"11-beta-Hydroxysteroid dehydrogenase of rat lung: enzyme kinetic, oxidase-reductase ratio, electrolyte and trace element dependence.","authors":"S Hundertmark, V Ragosch, B Schein, H Bühler, M Fromm, U Lorenz, H K Weitzel","doi":"10.1159/000468661","DOIUrl":"https://doi.org/10.1159/000468661","url":null,"abstract":"The modulation of the intracellular glucocorticoidal effect on surfactant synthesis of the fetal lung by the metabolic capacity of 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) could be an important factor in lung maturation. The kinetic properties of microsomal 11 beta-HSD of the rat lung are characterized with respect to product inhibition, substrate specificity, effect of electrolytes or trace elements, and the dependence of the oxidase reductase (OR) ratio on incubation conditions. With NADP+ product inhibition of the reductase was demonstrated. The most common trace elements and electrolytes exhibited no effect on the activity of 11 beta-HSD. It is shown that the OR ratio was strongly dependent on assay conditions. With optimal assay conditions oxidase activity exceeds reductase activity in adult and fetal rat lung microsomes (OR ratio > 1). Thus, glucocorticoids are mainly metabolized to their inactive forms. The enzyme activity in the adult is about 10 times higher than in the fetal lung. The low enzyme activity in fetal lungs could be the reason why the glucocorticoidal effects on surfactant synthesis are not suppressed despite the predominance of oxidase activity.","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/10.1159/000468661","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19183599","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: 11

A novel ornithine transcarbamylase present in mycoplasma-infected myeloma cells. 支原体感染的骨髓瘤细胞中存在一种新的鸟氨酸转甲氨基酶。

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468658

F Matsuno, H Matsuzaki, Y Akahoshi, M Yoshida, H Hata, M Takiguchi, K Takatsuki, M Mori

引用次数: 4

Molecular structure of 20S and 26S proteasomes. 20S和26S蛋白酶体的分子结构。

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468683

N Tanahashi, C Tsurumi, T Tamura, K Tanaka

{"title":"Molecular structure of 20S and 26S proteasomes.","authors":"N Tanahashi, C Tsurumi, T Tamura, K Tanaka","doi":"10.1159/000468683","DOIUrl":"https://doi.org/10.1159/000468683","url":null,"abstract":"Eukaryotic proteasomes are unusually large protein complexes with characteristic sets of subunits and have been classified into two isoforms with apparent sedimentation coefficients of 20S and 26S, respectively. The 20S proteasome (previously named the multicatalytic proteinase complex) is a cylindrical particle with a molecular weight (MW) of approximately 750 kD. It is a dimeric assembly of two symmetrical discs, each consisting of 7 alpha-type subunits and 7 beta-type subunits, having the molecular organization alpha n[1-7)beta n[1-7)beta n[1-7)alpha n[1-7), where 'n' indicates the number of heterogeneous 7 subunits with MWs of 21-32 kD. The alpha-type and beta-type subunits constitute a unique multi-gene family encoding previously unidentified, but homologous, polypeptides that have been conserved during evolution. Interestingly, some beta-type subunits with catalytic functions appear to be replaced by very homologous, but distinct, gene products that might be generated by gene duplication in response to extracellular signals, such as gamma-interferon, suggesting that the 20S proteasome exists in cells as a heterogeneous population with functional diversity. The 26S proteasome is a eukaryotic ATP-dependent protease, selectively degrading various cellular proteins with specific degradation signals such as a multi-ubiquitin chain. It is a cylindrical caterpillar-shaped complex with a MW of about 2,000 kD. The 26S proteasome is a symmetrical assembly of a central 20S proteasome and a large terminal polypeptide complex with an apparent sedimentation coefficient of 22S. The terminal 22S subset consists of multiple components with MWs of 30-110 kD, which possibly have regulatory functions, and contains multiple ATPases, a de-ubiquitinating enzyme and the recognition molecule(s) for the target proteins. Thus the 26S proteasome is a multi-molecular assembly, consisting of the 20S proteasome and the 22S regulatory subunit complex.","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/10.1159/000468683","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18701245","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: 76

Regulatory proteins of the proteasome. 蛋白酶体的调节蛋白。

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468689

G N DeMartino, C A Slaughter

引用次数: 42

Catalytic components of the bovine pituitary multicatalytic proteinase complex (proteasome). 牛垂体多催化蛋白酶复合物(蛋白酶体)的催化成分。

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468687

C Cardozo

引用次数: 38

2-Aminoadipate-2-oxoglutarate aminotransferase isoenzymes in human liver: a plausible physiological role in lysine and tryptophan metabolism. 人肝脏中的2-氨基己二酸-2-氧葡萄糖酸氨基转移酶同工酶:在赖氨酸和色氨酸代谢中的似是而非的生理作用。

Enzyme & protein Pub Date : 1993-01-01 DOI: 10.1159/000468669

E Okuno, M Tsujimoto, M Nakamura, R Kido

引用次数: 27