W C Kenney, W H Walker, E B Kearney, R Seng, T P Singer, J R Cronin, R Hendriks
Following elucidation of the structures of the flavin components of succinate dehydrogenase (SD) as N (3) -histidyl-8α-FAD and of monoamine oxidase (MAO) as cysteinyl-8α-FAD and determination of the peptide sequences around the flavin sites of these enzymes, attention has been focused on the covalently bound FAD of Chromatium cytochrome c-552. As documented in preliminary communications, the FAD moiety of this enzyme is also substituted at the 8α-position, as judged from ESR hyderfine structure of the free radical cation and the characteristic hypsochromic shift of the second absorption band of the neutral flavoquinone in purified preparations of the flavin. Definite proof has come from the liberation of 8-carbxyriboflavin on performic acid treatment of the enzyme. In regard to ESR and optical spectra and the tendency of the purified flavin (liberated by proteolysis) to undergo autooxidation with a further hypsochromic shift of the second absorption band and increased fluorescence, the flavin resembles the MAO flavin. The fact that fluorescence is >90% quenched at all pH values even at the FMN level and doees not vary with pH between 3.2 and 8 also suggests a thioether linkage as in cysteinyl riboflavin. In many respects, however, the Chromatium flavin differs from cysteinyl riboflavin. Highly purified preparations from tryptic-chymotryptic digests give a positive chloroplatinic test. Electrophoresis clearly shows the presence of carboxyl and amino groups but the peptide gives no characteristic ninhydrin reaction and amino acid analysis of performic acid oxidized samples yields cysteic acid and threonine in amounts less than equimolar to the flavin. The amino acid environment around the flavin may account for these results although a linkage other than a thioether remains a possibility.
{"title":"Recent advances in the chemistry of covalently bound flavin coenzymes.","authors":"W C Kenney, W H Walker, E B Kearney, R Seng, T P Singer, J R Cronin, R Hendriks","doi":"10.1515/znb-1972-0920","DOIUrl":"https://doi.org/10.1515/znb-1972-0920","url":null,"abstract":"Following elucidation of the structures of the flavin components of succinate dehydrogenase (SD) as N (3) -histidyl-8α-FAD and of monoamine oxidase (MAO) as cysteinyl-8α-FAD and determination of the peptide sequences around the flavin sites of these enzymes, attention has been focused on the covalently bound FAD of Chromatium cytochrome c-552. As documented in preliminary communications, the FAD moiety of this enzyme is also substituted at the 8α-position, as judged from ESR hyderfine structure of the free radical cation and the characteristic hypsochromic shift of the second absorption band of the neutral flavoquinone in purified preparations of the flavin. Definite proof has come from the liberation of 8-carbxyriboflavin on performic acid treatment of the enzyme. In regard to ESR and optical spectra and the tendency of the purified flavin (liberated by proteolysis) to undergo autooxidation with a further hypsochromic shift of the second absorption band and increased fluorescence, the flavin resembles the MAO flavin. The fact that fluorescence is >90% quenched at all pH values even at the FMN level and doees not vary with pH between 3.2 and 8 also suggests a thioether linkage as in cysteinyl riboflavin. In many respects, however, the Chromatium flavin differs from cysteinyl riboflavin. Highly purified preparations from tryptic-chymotryptic digests give a positive chloroplatinic test. Electrophoresis clearly shows the presence of carboxyl and amino groups but the peptide gives no characteristic ninhydrin reaction and amino acid analysis of performic acid oxidized samples yields cysteic acid and threonine in amounts less than equimolar to the flavin. The amino acid environment around the flavin may account for these results although a linkage other than a thioether remains a possibility.","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1069-71"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0920","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15507574","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}
K D Watenpaugh, L C Sieker, L H Jensen, J Le Gall, M Dubourdieu
{"title":"Flavodoxin from the sulfate reducing bacterium Desulfovibrio vulgaris. Its structure at 2.5 A resolution.","authors":"K D Watenpaugh, L C Sieker, L H Jensen, J Le Gall, M Dubourdieu","doi":"10.1515/znb-1972-0931","DOIUrl":"https://doi.org/10.1515/znb-1972-0931","url":null,"abstract":"","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1094-5"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0931","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15507585","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":"The structure of the network of the vessels of the carotid body of the cat and its evaluation by means of the scanning electron microscope.","authors":"H P Keller, D Schäfer, D W Lübbers","doi":"10.1515/znb-1972-0946","DOIUrl":"https://doi.org/10.1515/znb-1972-0946","url":null,"abstract":"","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1118"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0946","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15507589","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 interaction of flavinium salts with triphenylphosphine is described. The complexes which can be isolated in high yields in the crystalline state contain one mole triphenylphosphine per mole flavin. Triphenylphosphine is covalently bound to the N (5)-atom of the isoalloxazine ring system. Dissociation constants and rate constants have been determined spectrophotometrically. Evidence for the structure of the complex was obtained from light absorption, infrared and nuclear magnetic resonance studies. The similarities between the flavin-triphenylphosphine adduct and the earlier described flavin-sulfite adduct are described and the possible biological relevance of these complexes is discussed.
{"title":"On the interaction of flavins with phosphine-derivatives.","authors":"F Müller","doi":"10.1515/znb-1972-0904","DOIUrl":"https://doi.org/10.1515/znb-1972-0904","url":null,"abstract":"The interaction of flavinium salts with triphenylphosphine is described. The complexes which can be isolated in high yields in the crystalline state contain one mole triphenylphosphine per mole flavin. Triphenylphosphine is covalently bound to the N (5)-atom of the isoalloxazine ring system. Dissociation constants and rate constants have been determined spectrophotometrically. Evidence for the structure of the complex was obtained from light absorption, infrared and nuclear magnetic resonance studies. The similarities between the flavin-triphenylphosphine adduct and the earlier described flavin-sulfite adduct are described and the possible biological relevance of these complexes is discussed.","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1023-6"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0904","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15507559","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}
4a,5-Cycloaddition at the flavoquinone, Mechanism of flavoprotein inhibitions Photochemically, covalent cycloaddition products of flavoquinone and acetylenic enzyme inhibitors have been prepared and elucidated, which appear analogous to flavoprotein-inhibitor complexes (monoamine and lactate oxidase). The additions occur with inhibitors of general type HC≡C-CH< at the C (4a) = N (5) azomethine grouping of oxidized flavin. The spectral properties of adducts and their chemical reactivity is described.
{"title":"4a,5-Cycloaddiction reactions of acetylenic compounds at the flavoquinone nucleus as mechanisms of flavoprotein inhibitions.","authors":"E A Zeller, B Gärtner, P Hemmerich","doi":"10.1515/znb-1972-0913","DOIUrl":"https://doi.org/10.1515/znb-1972-0913","url":null,"abstract":"4a,5-Cycloaddition at the flavoquinone, Mechanism of flavoprotein inhibitions Photochemically, covalent cycloaddition products of flavoquinone and acetylenic enzyme inhibitors have been prepared and elucidated, which appear analogous to flavoprotein-inhibitor complexes (monoamine and lactate oxidase). The additions occur with inhibitors of general type HC≡C-CH< at the C (4a) = N (5) azomethine grouping of oxidized flavin. The spectral properties of adducts and their chemical reactivity is described.","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1050-2"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0913","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15507567","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}
S Yamamoto, F Hirata, T Yamauchi, M Nozaki, O Hyaishi
The spectral changes of the enzyme-bound FAD were investigated in the anaerobic and aerobic reactions of lysine monooxygenase, a flavoprotein. Under anaerobic conditions, the enzyme FAD was fully reduced with lysine via a transient intermediate having a broad absorption band in the long wavelength region. This anaerobic species was presumably involved in the dehydrogenation of lysine leading to the formation of an α-keto acid. During the steady state of the aerobic reaction, a separate spectral species with a long wavelength absorption was observed. Both lysine and oxygen were required for its appearance. Kinetic evidence supports the intermediacy of this species in the oxygenation of lysine to an acid amide.
{"title":"Spectrophotometric studies on lysine monooxygenase, a flavoprotein.","authors":"S Yamamoto, F Hirata, T Yamauchi, M Nozaki, O Hyaishi","doi":"10.1515/znb-1972-0916","DOIUrl":"https://doi.org/10.1515/znb-1972-0916","url":null,"abstract":"The spectral changes of the enzyme-bound FAD were investigated in the anaerobic and aerobic reactions of lysine monooxygenase, a flavoprotein. Under anaerobic conditions, the enzyme FAD was fully reduced with lysine via a transient intermediate having a broad absorption band in the long wavelength region. This anaerobic species was presumably involved in the dehydrogenation of lysine leading to the formation of an α-keto acid. During the steady state of the aerobic reaction, a separate spectral species with a long wavelength absorption was observed. Both lysine and oxygen were required for its appearance. Kinetic evidence supports the intermediacy of this species in the oxygenation of lysine to an acid amide.","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1056-7"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0916","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15507570","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 photoreactions of the flavin triplet with unsaturated hydrocarbons, aldehydes, sulphur compounds, and carbonic acids are reported. These reactions proceed by attack at the allylic C-H-, the RCO-H-, or the α-C-H-bond, respectively; in the case of carbonic acids decarboxylation occurs. In all the reported reactions covalent adducts are formed, whose structure and mode of decay is characterized.
{"title":"Covalent intermediates in flavin-sensitized photodehydrogenation and photodecarboxylation.","authors":"W R Knappe, P Hemmerich","doi":"10.1515/znb-1972-0907","DOIUrl":"https://doi.org/10.1515/znb-1972-0907","url":null,"abstract":"The photoreactions of the flavin triplet with unsaturated hydrocarbons, aldehydes, sulphur compounds, and carbonic acids are reported. These reactions proceed by attack at the allylic C-H-, the RCO-H-, or the α-C-H-bond, respectively; in the case of carbonic acids decarboxylation occurs. In all the reported reactions covalent adducts are formed, whose structure and mode of decay is characterized.","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1032-5"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0907","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15507561","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":"pH-dependence, isotope effect and products of flavin-sensitized photodecarboxylation and photodehydrogenation.","authors":"W Haas, P Hemmerich","doi":"10.1515/znb-1972-0908","DOIUrl":"https://doi.org/10.1515/znb-1972-0908","url":null,"abstract":"","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1035-7"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0908","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15507562","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 roles of enzyme-bound FAD and non-heme iron in the mechanism of adenylyl sulfate reductase have been investigated by inhibitor studies, stopped-flow techniques and EPR spectroscopy. The results indicate that the non-heme iron found in the purified reductase is catalytically active and that the turnover number of the enzyme-bound FAD is identical with the maximum turnover number for the enzyme.
{"title":"On the mechanism of adenylyl sulfate reductase for the sulfate-reducing bacterium, Desulfovibrio vulgaris.","authors":"H D Peck, R Bramlett, D V Der Vartanian","doi":"10.1515/znb-1972-0928","DOIUrl":"https://doi.org/10.1515/znb-1972-0928","url":null,"abstract":"The roles of enzyme-bound FAD and non-heme iron in the mechanism of adenylyl sulfate reductase have been investigated by inhibitor studies, stopped-flow techniques and EPR spectroscopy. The results indicate that the non-heme iron found in the purified reductase is catalytically active and that the turnover number of the enzyme-bound FAD is identical with the maximum turnover number for the enzyme.","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1084-6"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0928","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15507582","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}
E. coli NADPH-sulfite reductase, depleted of FMN but retaining its FAD, has been prepared by photoirradiation of native enzyme in 30% — saturated ammonium sulfate. FMN-depleted enzyme loses its ability to reduce (using NADPH) ferricyanide, cytochrome c, sulfite, or the enzyme’s own heme-like chromophore. However, the FAD remains rapidly reducible by NADPH, and the FMN-depleted enzyme retains NADPH-acetylpyridine NADP* transhydrogenase activity. Thus, FAD can serve as entry port for NADPH electrons, and FMN is required for further transmission along the enzyme’s electron transport chain. These data, plus other studies, have enabled us to suggest a mechanism for catalysis which involves FAD cycling between the fully-oxidized and fully-reduced forms while FMN cycles between fully-reduced and semiquinone. This mechanism, which includes a disproportionation step, permits a “step-down” from the twoelectron donor, NADPH, to a succession of equipotential one-electron transfer steps.
{"title":"Flavin interaction in NADPH-sulfite reductase.","authors":"L M Siegel, E J Faeder, H Kamin","doi":"10.1515/znb-1972-0929","DOIUrl":"https://doi.org/10.1515/znb-1972-0929","url":null,"abstract":"E. coli NADPH-sulfite reductase, depleted of FMN but retaining its FAD, has been prepared by photoirradiation of native enzyme in 30% — saturated ammonium sulfate. FMN-depleted enzyme loses its ability to reduce (using NADPH) ferricyanide, cytochrome c, sulfite, or the enzyme’s own heme-like chromophore. However, the FAD remains rapidly reducible by NADPH, and the FMN-depleted enzyme retains NADPH-acetylpyridine NADP* transhydrogenase activity. Thus, FAD can serve as entry port for NADPH electrons, and FMN is required for further transmission along the enzyme’s electron transport chain. These data, plus other studies, have enabled us to suggest a mechanism for catalysis which involves FAD cycling between the fully-oxidized and fully-reduced forms while FMN cycles between fully-reduced and semiquinone. This mechanism, which includes a disproportionation step, permits a “step-down” from the twoelectron donor, NADPH, to a succession of equipotential one-electron transfer steps.","PeriodicalId":78857,"journal":{"name":"Zeitschrift fur Naturforschung. Teil B. Anorganische Chemie, organische Chemie, Biochemie, Biophysik, Biologie","volume":"27 9","pages":"1087-9"},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znb-1972-0929","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15507583","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}
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