Biliverdin Dimethyl Ester Research Articles

Solution Conformations, Photophysics, and Photochemistry of Bile Pigments; Bilirubin and Biliverdin, Dimethyl Esters and Related Linear Tetrapyrroles

AbstractBilirubin and biliverdin dimethyl esters (BRE and BVE, respectively) and related linear tetrapyrroles have been studied using a combination of photochemical and spectroscopic techniques, the latter including absorption, fluorescence fluorescence excitation, medium‐induced circular dichroism, and proton magnetic resonance. Both types of tetrapyrroles form mixtures of different topological isomers in very dilute solutions. In the case of the bilirubins the heterogeneity of the solutions is caused by two coexisting conformers with different orientations of the A/B and C/D pyrromethenone moieties with repect to each other. The spectral properties of one conformer resemble the isolated parent pyrromethenone, whereas those of the other result from electronic coupling of the two subchromophores presumably held in a “ridge tile” ‐like orientation. CC rotations at the C‐5 and C‐15 bridges substantially compete in both components with the photochemical channels (E→Z isomerization and lumirubin formation) for the radiationless deactivation of the excited singlet state. The more rigid “ridge tile” component additionally undergoes hydrogen bond‐mediated deactivation, and it photoisomerizes more efficiently. The situation is markedly more complex with the biliverdins. In order to obtain a more detailed insight into the mechanisms of the radiationless excited‐state processes, time‐resolved optoacoustic spectroscopy and ultrafast absorption (pump‐probe) and fluorescence detection (single‐photon‐timing) techniques were used to supplement the stationary methods. The solution mixtures are composed of a (family of) helically coiled all‐Z, all‐syn species, and of species differing from the former by stretched arrangements of the rings B and C around the central C‐10 bridge (E‐anti, E‐syn, and Z‐anti). Two excited singlet states with picosecond lifetimes are attributed to either one or two coiled ground‐state forms, and two remarkably long‐lived nanosecond excited states arise each from a stretched ground state. The radiationless deactivation of the shorter‐lived of the picosecond states is brought about by ultrafast intramolecular proton transfer between the B/C nitrogen atoms, in addition to the CC rotational modes operative in both. Z→E photoisomerization is also an appreciable deactivation channel of excited biliverdin dimethyl ester. It is confined to the central C‐10 double bond and selectively affords a stretched isomer (10E‐anti), which thermally reforms the coiled starting meterial at room temperature via a sequence of tautomerization and CC rotation. Heating or ultrasonic treatment can reverse this sequence and drive it farther to populate another stretched isomer (10E‐syn) which is thermally stable at room temperature. This stretched form aggregates (presumably to dimers) already at concentrations at which the coiled species still appears to be fully monomeric.

Photoprocesses in biliverdin dimethyl ester in ethanol studied by laser-induced optoacoustic spectroscopy (lioas)

Laser-induced optoacoustic spectroscopy was applied to biliverdin dimethyl ester (BVE) in 95 % ethanol. The acoustic wave generated after dye-laser irradiation (λ exc = 630–680 nm) provided a measure of α, the “prompt” heat dissipation. The latter is denfied as the fraction of energy converted to heat by excited BVE in a time shorter than that (t 1, ca 1 μs) required to generate the acoustic wave. The value of α varied from 0.4 to 1 with the BVE concentration increasing from 10 −6 to 1.3 x 10 −5 M. The loss of heat at the low BVE concentrations is explained in terms of a photoisomerization of BVE, followed by thermal reversion to ground-state BVE in a time longer than t 1. Structural possibilities for the previously unknown photoisomer(s) are discussed. Static inhibition of the formation of the photoisomer(s) through some sort of association of an unidentified quencher with ground state BVE is proposed to cause the concentration dependence of α. The previously published scheme, which attributed the fluorescence of BVE to monomeric conformers, is thus extended to include the associated species which account for the concentration dependence of the optoacoustic data.

Picosecond Kinetics of Excited State Relaxation in Biliverdin Dimethyl Ester

AbstractThe relaxation processes of biliverdin IXα dimethyl ester have been studied by time‐resolved absorption and fluorescence detection, using pump‐probe and single‐photon timing techniques, respectively. The results complement and extend those of earlier investigations.1,3–5 In 2‐methyltetrahydrofuran, chloroform, ethanol, and ethyl lactate, four emitting species, two short‐lived (picosecond) and two long‐lived ones (nanosecond), have been detected. In methanol, the number of emitters is possibly reduced to three. In the cases of four emitters, these can be attributed to either three or four ground state forms. We conclude that the radiationless relaxation of the short‐lived excited states is simultaneously induced both by proton transfer processes and by conformational changes, as previously discussed.3 The spectroscopic properties of the long‐lived species point to the presence of relatively rigid conformations of the bilatriene in liquid solutions at room temperature. The possible relevance of this observation with regard to the influence of protein interactions on the conformational equilibrium of tetrapyrroles in phycobiliproteins is discussed.

Evidence for diastereoisomerism of biliverdin dimethyl ester dimers in the crystal lattice

Biliverdin dimethyl ester has been found to give different crystals depending on the solvent from which it is crystallized. It is concluded, based on IR and Raman data, that his polymorphism is attributable to the coexistence of different diastereoisomeric bishelical dimers in the crystal lattice.

Phytochrome models. 6. Conformation control by membrane of biliverdin dimethyl ester incorporated into lipid vesicles

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhytochrome models. 6. Conformation control by membrane of biliverdin dimethyl ester incorporated into lipid vesiclesInga Mai Tegmo-Larsson, Silvia E. Braslavsky, Stephen Culshaw, Raymond M. Ellul, Claude Nicolau, and Kurt SchaffnerCite this: J. Am. Chem. Soc. 1981, 103, 24, 7152–7158Publication Date (Print):December 1, 1981Publication History Published online1 May 2002Published inissue 1 December 1981https://doi.org/10.1021/ja00414a019RIGHTS & PERMISSIONSArticle Views67Altmetric-Citations22LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (809 KB) Get e-Alerts Get e-Alerts

Picosecond study of radiationless relaxation processes in biliverdin dimethyl ester

Picosecond study of radiationless relaxation processes in biliverdin dimethyl ester

Phytochrome Models. IV. Conformational Heterogeneity and Photochemical Changes of Biliverdin Dimethyl Esters in Solution

AbstractSolutions of biliverdin dimethyl ester (I) and its monoprotonated form (IH+) exhibit a solvatochromic and thermochromic behaviour. Based on absorption, fluorescence and fluorescence excitation, and solvent‐induced circular dichroism (SICD) data, these properties are interpreted in terms of variations of the relative populations of conformers (including readily interconvertible configurational isomers). Thus, folded helical forms of I and IH+ are more abundant at room temperature in, e.g., ethanol than in ethyl lactate, and stretched conformations other than the already known stable (E, Z, Z) and (Z, Z, E) photoisomers are quite generally favoured with increasing temperature. Irradiation of I in ethanol at 173 K increases the population with stretched, thermally equilibrating conformers. IH+ in ethanol undergoes an irreversible photochemical change at room temperature or below. Its nature has not yet been identified.

Conformational control by membrane of biliverdin dimethyl ester incorporated into liposomes, fluorescence and membrane-induced circular dichroism

Conformational control by membrane of biliverdin dimethyl ester incorporated into liposomes, fluorescence and membrane-induced circular dichroism

High-performance liquid chromatographic separation and quantification of the four biliverdin dimethyl ester isomers of the IX series

High-performance liquid chromatography (hplc) has been used to separate and quantificate the dimethyl ester (DME) derivatives of the four biliverdin isomers of the IX series: biliverdin-IXα, -IXβ, -IXγ, and -IXδ. Samples of 0.5 to 10.0 nmol of biliverdin DME were detected quantitatively upon elution by monitoring the absorbance at 375 nm. A technique was developed in which p-bromoacetanilide (Dupont's recommended test compound for their Zorbax column) is used as a marker for biliverdin-IXα DME. To facilitate quantification of biliverdin-IXβ DME, its extinction coefficient was determined. This method has been used to study biliverdin isomers in various biological species. High-resolution NMR (360 MHz) was used to further characterize the isomers.

ChemInform Abstract: SPECTROSCOPIC STUDIES ON MODEL COMPOUNDS OF THE PHYTOCHROME CHROMOPHORE. PROTONATION AND DEPROTONATION OF BILIVERDIN DIMETHYL ESTER

Chemischer InformationsdienstVolume 10, Issue 19 Physical Organic Chemistry ChemInform Abstract: SPECTROSCOPIC STUDIES ON MODEL COMPOUNDS OF THE PHYTOCHROME CHROMOPHORE. PROTONATION AND DEPROTONATION OF BILIVERDIN DIMETHYL ESTER L. MARGULIES, L. MARGULIESSearch for more papers by this authorM. STOCKBURGER, M. STOCKBURGERSearch for more papers by this author L. MARGULIES, L. MARGULIESSearch for more papers by this authorM. STOCKBURGER, M. STOCKBURGERSearch for more papers by this author First published: May 8, 1979 https://doi.org/10.1002/chin.197919051Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume10, Issue19May 8, 1979 RelatedInformation

THE TRIPLET EXCITED STATES OF BILIVERDIN AND BILIVERDIN DIMETHYL ESTER

Abstract— The triplet states of biliverdin and biliverdin dimethyl ester have been generated using pulse radiolysis excitation. Biliverdin triplet was formed by energy transfer from biphenyl triplet in acetone, absorbed throughout the wavelength range studied (380–1000 nm) and had a half‐life of 11.7μs under the cpnditions chosen. Biliverdin dimethyl ester triplet was formed by energy transfer from biphenyl triplet in benzene, likewise absorbed throughout the wavelength range studied (360–1000 nm) and had a half‐life of 6.7μs under the conditions used. Both biliverdin and biliverdin dimethyl ester efficiently quench anthracene, naphthacene, but not μ‐carotene, triplet states. On the other hand. neither μ‐carotene nor oxygen were found to quench the triplet states of biliverdin or biliverdin dimethyl ester. Estimates or limits for the rate constants of all these quenching reactions were obtained. These reactivities suggest that the triplet levels of both biliverdin and biliverdin dimethyl ester lie around 90 kJ mol‐1. The triplet energy transfer rate from bilirubin to biliverdin dimethyl ester in benzene was measured to be 1.9 × 109 M‐1 s‐1. The singlet‐triplet intersystem crossing efficiencies of both molecules were very low, limits of 0.004 and 0.001 being found for biliverdin and biliverdin dimethyl ester, respectively, using 347 nm laser excitation.

ChemInform Abstract: THE FLUORESCENCE OF BILIVERDIN DIMETHYL ESTER

Freshly prepared solutions of biliverdin dimethyl ester (2) in ethanol showed fluorescence maxima at 710 and 770 nm [ΦF = 1.1. 10−4 (room temperature) and 5.0 10−4 (77 K)]. The maxima of monoprotonated 2 at 77 K were shifted to 725 and 806 nm and the quantum yield was increased to 2.6. 10−2. This acid effect was reversible by neutralization with base. When a neutral solution was kept standing in the dark at room temperature, or when an acidic solution was neutralized by base, an additional fluorescence maximum at 500 nm with a mirror image excitation spectrum with λmax = 470 nm developed, which disappeared on addition of acid and which is attributed to a chemical change of 2.

Spectroscopic studies on model compounds of the phytochrome chromophore. Protonation and deprotonation of biliverdin dimethyl ester

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSpectroscopic studies on model compounds of the phytochrome chromophore. Protonation and deprotonation of biliverdin dimethyl esterLeon Margulies and Manfred StockburgerCite this: J. Am. Chem. Soc. 1979, 101, 3, 743–744Publication Date (Print):January 1, 1979Publication History Published online1 May 2002Published inissue 1 January 1979https://doi.org/10.1021/ja00497a046RIGHTS & PERMISSIONSArticle Views135Altmetric-Citations29LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (273 KB) Get e-Alerts Get e-Alerts

Phytochrome Models, I. Isolation, Characterization, and Solution Conformation of Biliverdin Dimethyl Ester and Its XIIIα Isomer

AbstractBiliverdin dimethyl ester (1b; IXα) and its XIIIα isomer 2b have been isolated on a preparative scale after esterification of an isomeric mixture obtained by oxidation of bilirubin. Both isomers readily form solid solutions. The substitution patterns and the predominant helical „all‐Z”︁ configuration, „all‐syn”︁ conformation of 1b and 2b are assigned on the basis of an 1H‐NMR study including spin decoupling and nuclear Overhauser effect experiments. The electronic absorption spectra of the two isomers differ significantly. The ethyl (S)‐(‐)‐lactate‐induced circular dichroism of 1b and 2b in the long and short wavelength regions is similar to that found for biliverdin‐peptide complexes.

The fluorescence of biliverdin dimethyl ester

AbstractFreshly prepared solutions of biliverdin dimethyl ester (2) in ethanol showed fluorescence maxima at 710 and 770 nm [ΦF = 1.1. 10−4 (room temperature) and 5.0 10−4 (77 K)]. The maxima of monoprotonated 2 at 77 K were shifted to 725 and 806 nm and the quantum yield was increased to 2.6. 10−2. This acid effect was reversible by neutralization with base. When a neutral solution was kept standing in the dark at room temperature, or when an acidic solution was neutralized by base, an additional fluorescence maximum at 500 nm with a mirror image excitation spectrum with λmax = 470 nm developed, which disappeared on addition of acid and which is attributed to a chemical change of 2.

ChemInform Abstract: CRYSTAL AND MOLECULAR STRUCTURE OF BILIVERDIN DIMETHYL ESTER

Chemischer InformationsdienstVolume 8, Issue 5 Physical Organic Chemistry ChemInform Abstract: CRYSTAL AND MOLECULAR STRUCTURE OF BILIVERDIN DIMETHYL ESTER W. S. SHELDRICK, W. S. SHELDRICKSearch for more papers by this author W. S. SHELDRICK, W. S. SHELDRICKSearch for more papers by this author First published: February 1, 1977 https://doi.org/10.1002/chin.197705077Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume8, Issue5February 1, 1977 RelatedInformation

Crystal and molecular structure of biliverdin dimethyl ester

Crystals of the title compound (II) are triclinic, space group P, with a= 12.467(6), b= 14.567(5), c= 9.788(4)Åα= 111.56(3), β= 90.64(4), γ= 97.91(3)°, Z= 2. The biliverdin chromophore, which is in the lactam form with three ‘pyrrole’ N–H protons, takes up a near-planar helical conformation. Two such molecules, related by a crystallographic centre of symmetry are linked into dimers with an extended helical conformation, through two N–H ⋯ O hydrogen bonds (N–H ⋯ O 2.80, N–H 1.12, H ⋯ O 1.74 Å) between symmetry-equivalent pyrrolone rings. A considerable degree of bond fixation is observed within the tetrapyrrole skeleton. The vinyl and one of the methyl ester groups are disordered. The structure was solved by direct methods and refined to R 0.090 for 2 357 diffractometer-measured unique reflections.

The isomeric heterogeneity of biliverdin dimethyl ester derived from bilirubin

Dehydrogenation of bilirubin with benzoquinone in acetic acid, followed by methylation, gives three isomeric biliverdin dimethyl esters, structures for which are suggested.