3-methyllumiflavin, irradiated in the first flavin band, forms a N-5 adduct in pyridine solutions. The possible nature of this adduct is discussed, together with the effect of water on the course of the photoreduction reaction.
{"title":"Photochemically induced adduct formation with flavin in pyridine.","authors":"A de Kok, C F Peters","doi":"10.1515/znb-1972-0903","DOIUrl":"https://doi.org/10.1515/znb-1972-0903","url":null,"abstract":"3-methyllumiflavin, irradiated in the first flavin band, forms a N-5 adduct in pyridine solutions. The possible nature of this adduct is discussed, together with the effect of water on the course of the photoreduction reaction.","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1021-2"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0903","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15510263","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}
The enzyme was anaerobically isolated and was characterized as a flavoprotein containing at least 1 FMN, 5-8 Fe and 7-8 moles labile sulfide per mole (M. W. appr. 300.000). It catalyzes the oxidation of formate by NAD, O2 (forming H2O2) and dyes and the oxidation of NADH by O2 (forming Η2Ο2) and dyes. It is irreversibly inhibited by formate.
{"title":"Some properties of formate dehydrogenase.","authors":"T Höpner, A Trautwein","doi":"10.1515/znb-1972-0923","DOIUrl":"https://doi.org/10.1515/znb-1972-0923","url":null,"abstract":"The enzyme was anaerobically isolated and was characterized as a flavoprotein containing at least 1 FMN, 5-8 Fe and 7-8 moles labile sulfide per mole (M. W. appr. 300.000). It catalyzes the oxidation of formate by NAD, O2 (forming H2O2) and dyes and the oxidation of NADH by O2 (forming Η2Ο2) and dyes. It is irreversibly inhibited by formate.","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1075-6"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0923","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15507577","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}
Catalysis by lipoamide dehydrogenase involves the concerted action of the flavin and a cystine residue. Peptides containing this cystine residue have been previously isolated from E. coli and now from pig heart. The sequences of amino acid residues reveal a high degree of homology indicating a strict conservation of the region around the active site cystine during the long evolutionary period between these two species. The peptide sequences suggest a likely conformation of the polypeptide chain in the region of the flavin as well as the forces involved in substrate and flavin binding.
{"title":"Sequence around the active center cystine of lipoamide dehydrogenase from pig heart, comparison with the E. coli enzyme.","authors":"C H Williams, L D Arscott","doi":"10.1515/znb-1972-0925","DOIUrl":"https://doi.org/10.1515/znb-1972-0925","url":null,"abstract":"Catalysis by lipoamide dehydrogenase involves the concerted action of the flavin and a cystine residue. Peptides containing this cystine residue have been previously isolated from E. coli and now from pig heart. The sequences of amino acid residues reveal a high degree of homology indicating a strict conservation of the region around the active site cystine during the long evolutionary period between these two species. The peptide sequences suggest a likely conformation of the polypeptide chain in the region of the flavin as well as the forces involved in substrate and flavin binding.","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1078-80"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0925","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15507579","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}
{"title":"Amino acid sequences of Clostridium pasteurianum flavodoxin.","authors":"J L Fox, S S Smith, J R Brown","doi":"10.1515/znb-1972-0932","DOIUrl":"https://doi.org/10.1515/znb-1972-0932","url":null,"abstract":"","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1096-100"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0932","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15507586","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}
{"title":"Photo-addition reactions in the benzenoid subnucleus of flavoquinones.","authors":"G Schöllnhammer, P Hemmerich","doi":"10.1515/znb-1972-0906","DOIUrl":"https://doi.org/10.1515/znb-1972-0906","url":null,"abstract":"","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1030-1"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0906","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15507560","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}
The reduction of aldehydes by flavohydroquinone to yield the corresponding alcohols and flavoquinone is reported and discussed in view of its relevance to the mechanism of flavin-dependent dehydrogenation and carbonyl activation. With formaldehyde and flavohydroquinone formation of a covalent 5- (HO - CH2) Flred⁻ intermediate species is observed. In a reverse reaction 5-methylflavoquinonium cation undergoes an internal redox reaction to yield flavohydroquinone and formaldehyde.
{"title":"Model studies on flavin-dependent carbonyl-activation: reduction of carbonyl compounds by flavohydroquinone.","authors":"G Blankenhorn, S Ghisla, P Hemmerich","doi":"10.1515/znb-1972-0909","DOIUrl":"https://doi.org/10.1515/znb-1972-0909","url":null,"abstract":"The reduction of aldehydes by flavohydroquinone to yield the corresponding alcohols and flavoquinone is reported and discussed in view of its relevance to the mechanism of flavin-dependent dehydrogenation and carbonyl activation. With formaldehyde and flavohydroquinone formation of a covalent 5- (HO - CH2) Flred⁻ intermediate species is observed. In a reverse reaction 5-methylflavoquinonium cation undergoes an internal redox reaction to yield flavohydroquinone and formaldehyde.","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1038-40"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0909","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15507563","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}
Nitroalkanes have been found to be general reductive substrates for D-amino acid oxidase, glucose oxidase and L-amino acid oxidase. These enzymes show different specificities for the structure of the nitroalkane substrate. The stoichiometry of the D-amino acid oxidase reaction is straightforward, consisting of the production of one mole each of aldehyde, nitrite and hydrogen peroxide for each mole of nitroalkane and oxygen consumed. The stoichiometry of the glucose oxidase reaction is more complex in that less than one mole of hydrogen peroxide and nitrite is produced and nitrate and traces of 1-dinitroalkane are formed. The kinetics of nitroalkane oxidation show that the nitroalkane anion is much more reactive in reducing the flavin than is the neutral substrate. The pH dependence of flavin reduction strongly suggests that proton abstraction is a necessary event in catalysis. A detailed kinetic mechanism is presented for the oxidation of nitroethane by glucose. It has been possible to trap a form of modified flavin in the reaction of D-amino acid oxidase with nitromethane from which oxidized FAD can be regenerated in aqueous solution in the presence of oxygen.
{"title":"Nitroalkanes as reductive substrates for flavoprotein oxidases.","authors":"D J Porter, J G Voet, H J Bright","doi":"10.1515/znb-1972-0914","DOIUrl":"https://doi.org/10.1515/znb-1972-0914","url":null,"abstract":"Nitroalkanes have been found to be general reductive substrates for D-amino acid oxidase, glucose oxidase and L-amino acid oxidase. These enzymes show different specificities for the structure of the nitroalkane substrate. The stoichiometry of the D-amino acid oxidase reaction is straightforward, consisting of the production of one mole each of aldehyde, nitrite and hydrogen peroxide for each mole of nitroalkane and oxygen consumed. The stoichiometry of the glucose oxidase reaction is more complex in that less than one mole of hydrogen peroxide and nitrite is produced and nitrate and traces of 1-dinitroalkane are formed. The kinetics of nitroalkane oxidation show that the nitroalkane anion is much more reactive in reducing the flavin than is the neutral substrate. The pH dependence of flavin reduction strongly suggests that proton abstraction is a necessary event in catalysis. A detailed kinetic mechanism is presented for the oxidation of nitroethane by glucose. It has been possible to trap a form of modified flavin in the reaction of D-amino acid oxidase with nitromethane from which oxidized FAD can be regenerated in aqueous solution in the presence of oxygen.","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1052-3"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0914","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15507568","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}
H J Grande, A J Visser, J L de Wit, F Müller, C Veeger
Maleimide spin label was covalently bound to sulfhydryl residues of ᴅ-amino acid oxidase and lipoamide dehydrogenase. Labeling of native ᴅ-amino acid oxidase resulted in a non-homogeneous EPR-spectrum, which consisted of 4 moles of spin label bound immobile to the enzyme (mol.-weight 90.000). A detailed analysis of the spectrum, the kinetics of the reaction of the spin label with the protein and the temperature dependence of the spectrum showed that the spectrum originates from two different pairs of sulfhydryl groups. The spin labeled lipoamide dehydrogenase yielded also a mixed EPR-spectrum of two different bound spin labels, i.e. an immobile and a semimobile species. The temperature dependence gave for both types of spectra a transition point at 10°C. Titration with urea gave only for the immobile species a transition at 1.5 M. Part of the semimobile species seems to be bound near the active site. ᴅ-amino acid oxidase was also specifically labeled, near the active site, with a substrate analogue. From its EPR-spectrum it appeared that the analogue was bound very mobile (τc=0.3 nsec) with respect to the protein. Removal of FAD had a drastic reversible effect on the spectrum.
{"title":"Spin label studies on the flavoproteins lipoamide dehydrogenase and D-amino acid oxidase.","authors":"H J Grande, A J Visser, J L de Wit, F Müller, C Veeger","doi":"10.1515/znb-1972-0917","DOIUrl":"https://doi.org/10.1515/znb-1972-0917","url":null,"abstract":"Maleimide spin label was covalently bound to sulfhydryl residues of ᴅ-amino acid oxidase and lipoamide dehydrogenase. Labeling of native ᴅ-amino acid oxidase resulted in a non-homogeneous EPR-spectrum, which consisted of 4 moles of spin label bound immobile to the enzyme (mol.-weight 90.000). A detailed analysis of the spectrum, the kinetics of the reaction of the spin label with the protein and the temperature dependence of the spectrum showed that the spectrum originates from two different pairs of sulfhydryl groups. The spin labeled lipoamide dehydrogenase yielded also a mixed EPR-spectrum of two different bound spin labels, i.e. an immobile and a semimobile species. The temperature dependence gave for both types of spectra a transition point at 10°C. Titration with urea gave only for the immobile species a transition at 1.5 M. Part of the semimobile species seems to be bound near the active site. ᴅ-amino acid oxidase was also specifically labeled, near the active site, with a substrate analogue. From its EPR-spectrum it appeared that the analogue was bound very mobile (τc=0.3 nsec) with respect to the protein. Removal of FAD had a drastic reversible effect on the spectrum.","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1058-62"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0917","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15507571","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}
{"title":"Metabolism of organophosphorus insecticides. XIV. Malathion breakdown by soil fungi.","authors":"I Y Mostafa, M R Bahig, I M Fakhr, Y Adam","doi":"10.1515/znb-1972-0944","DOIUrl":"https://doi.org/10.1515/znb-1972-0944","url":null,"abstract":"","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1115-6"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0944","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15507587","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}
M J Gibian, D L Elliott, C Kelly, B Borge, K Kupecz
A. Equilibrium and second-order rate constants have been measured for the redox reaction between phthaloquinone and dihydroriboflavin (and its reverse) at a number of pH values. The equilibria and kinetic determinations are in agreement. No intermediates could be found in the reaction, and it is proposed that with this and other quinones electron transfer occurs within a complex of the flavin and hydroquinone (or dihydroflavin and quinone). B. A survey of the reaction between mercaptans and flavins is reported, as well as data showing that with mercaptoethanol the reaction is reversible, the disulfide and reduced flavin giving mercaptan and flavin. C. The reaction of alkylphenone enolates with isoalloxazine is described. This reaction leads t 50% isoalloxazine radical anion and an adduct of the enolate with the ketone. A possible route for this process is discussed.
{"title":"Studies of reactions between flavins and quinones, mercaptans, and enolates.","authors":"M J Gibian, D L Elliott, C Kelly, B Borge, K Kupecz","doi":"10.1515/znb-1972-0902","DOIUrl":"https://doi.org/10.1515/znb-1972-0902","url":null,"abstract":"A. Equilibrium and second-order rate constants have been measured for the redox reaction between phthaloquinone and dihydroriboflavin (and its reverse) at a number of pH values. The equilibria and kinetic determinations are in agreement. No intermediates could be found in the reaction, and it is proposed that with this and other quinones electron transfer occurs within a complex of the flavin and hydroquinone (or dihydroflavin and quinone). B. A survey of the reaction between mercaptans and flavins is reported, as well as data showing that with mercaptoethanol the reaction is reversible, the disulfide and reduced flavin giving mercaptan and flavin. C. The reaction of alkylphenone enolates with isoalloxazine is described. This reaction leads t 50% isoalloxazine radical anion and an adduct of the enolate with the ketone. A possible route for this process is discussed.","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1016-20"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15510262","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：