Pyrroles and related compounds—VIII

Jackson, Anthony H.; Kenner, G. W.; Smith, Kimberly; Aplin, Robin T.; Budzikiewicz, H.; Djerassi, Carl

doi:10.1016/s0040-4020(01)98377-2

Cited by 103 publications

(26 citation statements)

References 7 publications

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“…With either of these structures we can explain another important fact we have previously not considered. That it is possible to record a mass spectrum of the acid is surprising in itself, since many tetrapyrrolic compounds with acid side chains, for example porphyrin derivatives [32], mesobiliverdin, and (probably) the oxophlorins [33,34], are insufficiently volatile for mass-spectrometric analysis. The relatively high volatility of bilirubin, mesobilirubin, the urobilins, and phycocyanobilin itself must be due [35] have shown that intramolecular hydrogen bonds are indeed formed in bilirubin.…”

Section: Xtructure Of Phycocyanobilinmentioning

confidence: 99%

Structure of Phycocyanobilin

Schram

Kroes

1971

European Journal of Biochemistry

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The structure of phycocyanobilin, the prosthetic group of phycocyanin, has been investigated by means of mass spectral, infrared, and nuclear magnetic resonance studies. The linear tetrapyrrolic compound has a molecular weight of 588 and contains an intramolecular hydrogen bond, the rupture of which forms the basis for several of the chemical transformations. Esterification, for example, is accompanied by dehydrogenation, so the molecular weight of the dimethyl ester is 614.The structure of the phycobilin P 655 has been deduced from an analysis of the properties of phycocyanobilin; this structure is nearly identical to the one proposed by Cole, Chapman, and Siegelman. For the phycobilin P 608 only a tentative structure can be presented.Phycocyanobilin is the prosthetic group of C-phycocyanin and allophycocyanin, both of which belong to the important class of photosynthetically active proteins of blue-green algae. Structural analysis of this coloured compound was started as long ago as 1933 when Lemberg and Bader [l] incorrectly identified it as the linear tetrapyrrole mesobiliviolin IXa. It was not until the extensive work of 6 hEocha [2] in 1963 that the complicated nature of phycocyanobilin became clear. 6 hEocha showed that three different pigments can be obtained, depending on the methods used to cleave the chromophore from the protein: he designated the three pigments he isolated P655, P630, and P608 on the basis of their Amax (nm) in acid chloroform. From the spectra of the pigment in the visible and ultraviolet regions, 6 hEocha concluded that the structure of the "native form" (P 630) was intermediate between that of mesobiliviolin and that of mesobiliverdin, but he was unable to give a detailed structure for phycocyanobilin at that time.We became interested in phycocyanobilin because of its assumed resemblance to the chromophore of phytochrome [3]. Since it is available in larger quantities than phytochrome we thought it an attractive model compound for our work on phytochrome: moreover with such powerful instrumental techniques as mass spectrometry, infrared spectrometry, and nuclear magnetic resonance spectrometry, we should be able to carry out a more detailed structural analysis than hitherto possible. During the course of our work two American research groups, namely Crespi and Katz [4,5] a t the Argonne National Laboratory, and Cole, Chapman, and Siegelman [6,7] a t the Brookhaven National Laboratory, reported the results of 39'their work on the structure of phycocyanobilin. Although the results of these two groups are in agreement as far as the nuclear magnetic resonance spectra are concerned, there remains a discrepancy between the mass spectrometry results: the former group found a molecular weight of 588 for the acid and the latter a molecular weight of 586, since they found the dimethyl ester to have a molecular weight of (We make extensive use of this notation in this paper, but the lettering has been omitted from the remaining Schemes for the sake of clarity.) Of great importance is the f...

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Section: Xtructure Of Phycocyanobilinmentioning

confidence: 99%

Structure of Phycocyanobilin

Schram

Kroes

1971

European Journal of Biochemistry

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“…Остальные интенсивные пики в масс-спектрах образуются в результате последовательного отрыва углеводородных заместителей пиррольных колец. Процесс, вероятно, протекает не только по пути отрыва CH 3 -групп от групп C 2 H 5 , отмеченному в работе [10] как наиболее вероятному для порфириновых комплексов, но и с отрывом самих этильных групп от макрогетероцикла, а также с отрывом метильных заместителей и этиленовых фрагментов. Для молекулярных ионов и ионов, образованных отрывом одной метильной группы, наблюдается полное согласие теоретически рассчитанных изотопных распределений с соответствующими экспериментальными результатами.…”

Section: результаты и обсужденияunclassified

“…[10][11][12][13][14][15] Авторами [16] особое внимание уделено термодинамике сублимации тетра-фенилпорфиринатов некоторых металлов. В ходе исследований были установлены следующие законо-мерности: в случае тетрагональной кристаллической решетки энтальпия сублимации комплексов увели-чивается с увеличением межъядерного расстояния M-N, тогда как для триклинных кристаллов обнару-жена обратная зависимость.…”

Section: Introductionunclassified

Mass-Spectrometric Study of Cobalt, Nickel, Copper and Zinc Etioporphyrin-II Sublimation

Pogonin¹,

Krasnov²,

Zhabanov³

et al. 2012

MHC

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“…Porphyrins, which are large, nitrogen-containing aromatic molecules, yield relatively high intensities of doubly charged molecular and fragment ions. 3 Porphyrins are of special interest in a variety of fields from geochemistry4 to cancer research.' Tandem mass spectrometry (MS/MS) has been shown to be a powerful approach for structure elucidation of porphyrins."'…”

Section: Introductionmentioning

confidence: 99%

Doubly charged porphyrin ion tandem mass spectrometry: Implications for structure elucidation

Beato

Yost

Quirke

1989

Org. Mass Spectrom.

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Under electron ionization (EI) conditions, porphyrins yield unusually high intensities of doubly charged molecular and fragment ions. These doubly charged ions offer unique opportunities for the structure elucidation of porphyrins by tandem mass spectrometry (MS/MS). First, they fragment to a greater extent than the corresponding singly charged ions under both EI/MS and EI/MS/MS conditions. Second, doubly and singly charged porphyrin ions often fragment via different pathways, and can therefore yield different structural information. This paper describes several ways in which analyses of doubly charged porphyrin ions with a triple quadrupole tandem mass spectrometer can be useful in structure elucidation of porphyrins. The effect of the metal atom on the fragmentation of metalloporphyrins in an EI source is demonstrated by correlating the extent of doubly charged fragment ion formation to a stability index. Doubly charged porphyrin ions are shown to yield predominantly doubly charged daughter ions upon collisionally activated dissociation (CAD), and are also shown to fragment to a greater extent than corresponding singly charged porphyrin ions. Advantages and disadvantages of doubly charged porphyrin ion MS/MS for structure elucidation are discussed.

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Pyrroles and related compounds—VIII

Cited by 103 publications

References 7 publications

Structure of Phycocyanobilin

Structure of Phycocyanobilin

Mass-Spectrometric Study of Cobalt, Nickel, Copper and Zinc Etioporphyrin-II Sublimation

Doubly charged porphyrin ion tandem mass spectrometry: Implications for structure elucidation

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