Biochimica et Biophysica Acta (BBA) - Enzymology最新文献_第2页

A latent thiol proteinase from ascitic fluid of patients with neoplasia 肿瘤患者腹水中潜伏的硫醇蛋白酶

Biochimica et Biophysica Acta (BBA) - Enzymology Pub Date : 1981-12-15 DOI: 10.1016/0005-2744(81)90027-9

John S. Mort, Michèle Leduc, Anneliese D. Recklies

引用次数: 58

The effects of anions, substrates, metal ions and sulfhydryl reagents on the proteolytic susceptibility of yeast phosphoglycerate kinase 阴离子、底物、金属离子和巯基试剂对酵母磷酸甘油酸激酶蛋白水解敏感性的影响

Biochimica et Biophysica Acta (BBA) - Enzymology Pub Date : 1981-12-15 DOI: 10.1016/0005-2744(81)90035-8

Jean A. Wrobel , Robert A. Stinso

{"title":"The effects of anions, substrates, metal ions and sulfhydryl reagents on the proteolytic susceptibility of yeast phosphoglycerate kinase","authors":"Jean A. Wrobel , Robert A. Stinso","doi":"10.1016/0005-2744(81)90035-8","DOIUrl":"10.1016/0005-2744(81)90035-8","url":null,"abstract":"<div>With the aim of confirming our previous spectrophotometric binding studies ((1978) Eur. J. Biochem. 85, 345–350 and (1980) Eur. J. Biochem. 104, 249–254) and of ascertaining the full physiological significance of ion binding, we investigated the effects of ions and thiol reagents on the proteolysis of yeast phosphoglycerate kinase (ATP : 3-phospho-d-glycerate 1-phosphotransferase, EC 2.7.2.3). The single non-essential thiol of the enzyme was modified with 5,5′-dithiobis(2-nitrobenzoic acid) or 2-chloromercuri-4-nitrophenol. Both modifications greatly increased the susceptibility of the kinase to inactivation by trypsin or yeast proteinase A, when compared with that of the native kinase. Electrophoresis in sodium dodecyl sulfate (SDS) revealed that limited proteolysis had occurred. The time courses for the proteolysis and loss of catalytic activity were followed and the active and inactive fragments identified. The molecular masses of the major proteolytic fragments differed with the two endopeptidases. Substrate and non-substrate anions in a concentration-dependent fashion, protected the native and mercurial-labelled kinase from inactivation by trypsin or yeast proteinase A. However, Zn2+, in a concentration-dependent fashion, increased the susceptibility of the native kinase to inactivation by each endopeptidase. The time courses for the inactivation and for the proteolysis allowed the active and inactive fragments to be identified. Zn2+ decreased the rate of inactivation of the mercurial-labelled kinase by proteinase A. The effects of these ions were detected at concentrations compatible with occupancy of an anion binding site and a low affinity Zn2+ binding site, both of which have been indicated from our previous binding studies.</div>","PeriodicalId":100159,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Enzymology","volume":"662 2","pages":"Pages 236-245"},"PeriodicalIF":0.0,"publicationDate":"1981-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0005-2744(81)90035-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18080715","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: 5

A protein kinase of the plasma membrane of Dictyostelium discoideum 盘状盘状钢质膜的一种蛋白激酶

Biochimica et Biophysica Acta (BBA) - Enzymology Pub Date : 1981-12-15 DOI: 10.1016/0005-2744(81)90037-1

Maria Helena Juliani , Claudette Klein

{"title":"A protein kinase of the plasma membrane of Dictyostelium discoideum","authors":"Maria Helena Juliani , Claudette Klein","doi":"10.1016/0005-2744(81)90037-1","DOIUrl":"10.1016/0005-2744(81)90037-1","url":null,"abstract":"<div>D. discoideum amoebae were found to phosphorylate plasma membrane proteins when intact cells were incubated with either [γ-32P]ATP or [32P]phosphate. In the first case, the incorporation was largely a consequence of the hydrolysis of [γ-32P]ATP, cellular uptake of the generated [32P]phosphate and its subsequent incorporation into ATP. When the contribution of this process to the phosphorylating activity of intact cells was eliminated, an ecto-protein kinase (ATP: protein phosphotransferase, EC 2.7.1.37) activity could be demonstrated. As amoebae progressed through their aggregation program, they showed a decreased ability to phosphorylate their plasma membrane when incubated with [γ-32P]ATP or [32P]phosphate. Analysis of ATPase activity, permeability properties and the pattern of proteins phosphorylated by intact cells and isolated plasma membranes lead to the following conclusions: the lower levels of phosphorylation observed with starved cells reflected an altered uptake of [32P]phosphate by these cells rather than a significant change in the plasma membrane protein kinase activity. Neither the substrates nor the activity of the ecto-protein kinase was dramatically altered during starvation.</div>","PeriodicalId":100159,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Enzymology","volume":"662 2","pages":"Pages 256-264"},"PeriodicalIF":0.0,"publicationDate":"1981-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0005-2744(81)90037-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18330382","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: 7

The protoporphyrin-apoperoxidase complex as a horseradish peroxidase analog 原卟啉-过氧化物酶复合物是一种辣根过氧化物酶类似物

Biochimica et Biophysica Acta (BBA) - Enzymology Pub Date : 1981-12-15 DOI: 10.1016/0005-2744(81)90032-2

N.N. Ugarova, A.P. Savitski, I.V. Berezin

{"title":"The protoporphyrin-apoperoxidase complex as a horseradish peroxidase analog","authors":"N.N. Ugarova, A.P. Savitski, I.V. Berezin","doi":"10.1016/0005-2744(81)90032-2","DOIUrl":"10.1016/0005-2744(81)90032-2","url":null,"abstract":"<div>Similarity of the protein tertiary structures of the native horseradish peroxidase (donor: hydrogen-peroxide oxidoreductase, EC 1.11.1.7) and protoporphyrin-apoperoxidase complex has been shown on the basis of identity of the tryptophan fluorescence parameter at pH 2.0–8.0 and of the circular dichroism spectra of the two proteins. Absorption and fluorescence spectra have been obtained for protoporphyrin in the complex in the pH range 7.0–1.6. A shift in the apparent pK by 4 units has been observed for protonation of the protoporphyrin pyrrolic ring in the complex. From this shift, the dielectric constant has been evaluated for the heme pocket of the peroxidase (approx. 20). Fluorescence quantum yield of protoporphyrin in the complex increased with pH decreasing from 5.0 to 3.5, whereas the spectrum pattern and fluorescence lifetime did not change. The ions, I− and [Fe(CN)6]−4, peroxidase substrates, did not quench the protoporphyrin fluorescence in the complex at about neutral pH, whereas the quenching markedly enhanced with lowering pH. The bimolecular constant for the I−-quenching of the porphyrin fluorescence in the complex showed a pH-dependence similar to that of the bimolecular rate constant for the reaction of peroxidase compound I with I−. A mechanism for I− oxidation at an acid pH in the presence of peroxidase has been proposed.</div>","PeriodicalId":100159,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Enzymology","volume":"662 2","pages":"Pages 210-219"},"PeriodicalIF":0.0,"publicationDate":"1981-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0005-2744(81)90032-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18330557","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: 34

Evidence for exchange of inhibitors which bind to the active site of trypsin 与胰蛋白酶活性位点结合的抑制剂交换的证据

Biochimica et Biophysica Acta (BBA) - Enzymology Pub Date : 1981-12-15 DOI: 10.1016/0005-2744(81)90029-2

F.S. Steven, M.M. Griffin

引用次数: 5

The membrane-bound hydrogenase of Rhodopseudomonas capsulata 荚膜红假单胞菌的膜结合氢化酶

Biochimica et Biophysica Acta (BBA) - Enzymology Pub Date : 1981-12-15 DOI: 10.1016/0005-2744(81)90039-5

Annette Colbeau, Paulette M. Vignais

{"title":"The membrane-bound hydrogenase of Rhodopseudomonas capsulata","authors":"Annette Colbeau, Paulette M. Vignais","doi":"10.1016/0005-2744(81)90039-5","DOIUrl":"10.1016/0005-2744(81)90039-5","url":null,"abstract":"<div>The hydrogenase of Rhodopseudomonas capsulata is an intrinsic membrane protein extractable from the membrane by detergents. Triton X-100 produces stable soluble extracts. Stability of solubilized hydrogenase depends drastically on two factors: temperature and gas-phase. The solubilised hydrogenase is more stable at 20°C than in the cold and is further stabilised under an H2 atmosphere. The kinetic properties of the membrane-bound and Triton-solubilised forms of the enzyme have been compared. Both forms of the enzyme show a pH optimum for the reduction of benzyl or methyl viologen at 8.5–9.0, for H2 production with methyl viologen semiquinone at 5.7 and for H2H exchange at 4.5. In vitro, the hydrogenase functions as a reversible enzyme although at a slower rate for H2 evolution than for H2 uptake. The apparent Km for H2 (uptake) is 0.25 μM. The artificial electron acceptors having the highest affinity for hydrogenase are methylene blue (Km = 60 μM) and benzyl viologen (Km = 100 μM). Methyl viologen has a higher affinity in the semiquinone form (Km = 450 μM) than in the oxidized dicationic form (Km = 3.6 mM). The Arrhenius plot of the activity of hydrogenase in the membrane and in the solubilised extract shows a break at 13°C. This transition temperature of 13°C is probably linked to a change of protein conformation. The activation energy is 110 kJ/mol (26.4 kcal/mol) adnd 38 kJ/mol (9.1 kcal/mol) below and above the transition temperature, respectively. While hydrogenase is a cold labile enzyme, it is remarkably resistant to heat inactivation, for example the membrane-bound form can withstand heating at 80°C for 3 h without loss of activity.</div>","PeriodicalId":100159,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Enzymology","volume":"662 2","pages":"Pages 271-284"},"PeriodicalIF":0.0,"publicationDate":"1981-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0005-2744(81)90039-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90188558","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: 36

Location of functional -SH groups in NADPH-cytochrome P-450 reductase from rabbit liver microsomes 兔肝微粒体nadph -细胞色素P-450还原酶功能-SH基团的定位

Biochimica et Biophysica Acta (BBA) - Enzymology Pub Date : 1981-12-15 DOI: 10.1016/0005-2744(81)90041-3

Yukio Nisimoto, Yukio Shibata

{"title":"Location of functional -SH groups in NADPH-cytochrome P-450 reductase from rabbit liver microsomes","authors":"Yukio Nisimoto, Yukio Shibata","doi":"10.1016/0005-2744(81)90041-3","DOIUrl":"10.1016/0005-2744(81)90041-3","url":null,"abstract":"<div>The total -SH content of purified NADPH-cytochrome P-450 reductase (NADPH: ferricytochrome oxidoreductase, EC 1.6.2.4) from rabbit liver microsomes accessible to an excess equivalent of PCMB was 7.0 ± 0.3 mol thiol groups/mol protein. The modification of four -SH groups at low concentrations of PCMB stimulated the activity of the enzyme. On the other hand, further blocking of -SH groups (6–7 mol -SH groups/mol protein) with an excess amount of PCMB completely inhibited cytochrome c (or DCPI) reductase activity. The fluorescence quenching of the flavin was rapidly removed by binding of PCMB to a fifth and sixth -SH group during a gradual titration. Kinetic and fluorimetric analyses confirmed the suggestion that these two -SH groups essential for catalytic function were partly protected by NADP+ or 2′-AMP against the reaction with PCMB. Excess PCMB begins to compete with the ligand preincubated with the enzyme. The spectral perturbation on the addition of approx. 6–7 equiv. PCMB/mol enzyme is accompanied by a slight blue shift of the absorbance maximum at 380 nm, with the appearance of a pronounced shoulder at 475 nm. In contrast to the native enzyme, 3-electron-reduced semiquinone form of PCMB-treated enzyme showed the same absorption spectrum as 1-electron-reduced semiquinone which has an absorption maximum at 585 nm with a broad shoulder around 635 nm. An inhibitory effect may be attributable to the fact that NADPH is less accessible to the FAD binding site as well as the pyridine nucleotide binding site, since the rate of FAD reduction becomes extremely slow after complete modification.</div>","PeriodicalId":100159,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Enzymology","volume":"662 2","pages":"Pages 291-299"},"PeriodicalIF":0.0,"publicationDate":"1981-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0005-2744(81)90041-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17849735","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

Kinetics of suicide substrates steady-state treatments and computer-aided exact solutions 自杀底物的动力学、稳态处理和计算机辅助精确解

Biochimica et Biophysica Acta (BBA) - Enzymology Pub Date : 1981-12-15 DOI: 10.1016/0005-2744(81)90034-6

Shinobu Tatsunami , Nagasumi Yago , Masanao Hosoe

{"title":"Kinetics of suicide substrates steady-state treatments and computer-aided exact solutions","authors":"Shinobu Tatsunami , Nagasumi Yago , Masanao Hosoe","doi":"10.1016/0005-2744(81)90034-6","DOIUrl":"10.1016/0005-2744(81)90034-6","url":null,"abstract":"<div>A steady-state differential equation that describes the kinetics of suicide substrate was derived for a scheme presented by Walsh et al. (Walsh, C., Cromartie, T., Marcotte, P. and Spencer, R. (1978) Methods Enzymol. 53, 437–448). Using its analytical solutions, the progress curves of substrate disappearance, product formation and enzyme inactivation were calculated for a hypothetical model system, and were compared with the exact solutions which were obtained by the numerical computation on a set of rate equations. The results obtained with the present analytical solutions were much more consistent with the exact solutions than those obtained using Waley's solutions (Waley, S.G. (1980) Biochem. J. 185, 771–773). The most important factor for a system of suicide substrates was found to be the term (1 + r)μ instead of rμ as proposed by Waley, where r is the ratio of the rate constant of product formation to that of enzyme inactivation and μ is the ratio of initial concentration of enzyme to that of suicide substrate. In cases where this term has a value greater than unity, all the molecules of suicide substrate are used up leaving some enzyme molecules still active. To the contrary, in cases where the term has a value smaller than unity, all the enzyme molecules are inactivated with some molecules of suicide substrate being left unreacted. When the term is equal to unity, then all the enzyme molecules are inactivated and all the molecules of the suicide substrate are converted. Practical methods for estimating kinetic parameters are described.</div>","PeriodicalId":100159,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Enzymology","volume":"662 2","pages":"Pages 226-235"},"PeriodicalIF":0.0,"publicationDate":"1981-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0005-2744(81)90034-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18330380","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: 66

Purification and properties of aldose 1-epimerase from aspergillus niger 黑曲霉醛糖1- epimase的纯化及性质研究

Biochimica et Biophysica Acta (BBA) - Enzymology Pub Date : 1981-12-15 DOI: 10.1016/0005-2744(81)90040-1

Shinichi Kinoshita, Keiichi Kadota, Hisaharu Taguchi

引用次数: 8

Purification of cathepsin D from rabbit skeletal muscle and its action towards myofibrils 兔骨骼肌组织蛋白酶D的纯化及其对肌原纤维的作用

Biochimica et Biophysica Acta (BBA) - Enzymology Pub Date : 1981-12-15 DOI: 10.1016/0005-2744(81)90031-0

Akihiro Okitani , Teruyo Matsumoto , Yohko Kitamura , Hiromichi Kato

引用次数: 55