Zobrazeno 1 - 10
of 14
pro vyhledávání: '"Michael Helfrich"'
Autor:
Oliver C. Singer, Steffen Volz, Ralf Deichmann, Luciana Porto, Michael Helfrich, Jörg Magerkurth, Elke Hattingen, Marlies Wagner, Stella Blasel, Alina Jurcoane
Publikováno v:
Neuroradiology. 57:1023-1030
Quantitative MRI with T2, T2*, and T2′ mapping has been shown to non-invasively depict microstructural changes (T2) and oxygenation status (T2* and T2′) that are invisible on conventional MRI. Therefore, we aimed to assess whether T2 and T2′ qu
Autor:
Harald Klement, Antony W.D. Larkum, Wolfhart Rüdiger, Birgit Bommer, Michael Helfrich, Karl Mayer, Ulrike Oster
Publikováno v:
Biochimica et Biophysica Acta (BBA) - Bioenergetics. 1605(1-3):97-103
Using circular dichroism (CD) spectroscopy, the stereochemistry at C-13(2) of members of the chlorophyll (Chl) c family, namely Chls c(1), c(2), c(3) and [8-vinyl]-protochlorophyllide a (Pchlide a) was determined. By comparison with spectra of known
Publikováno v:
European Journal of Biochemistry. 265:862-874
The enzyme NADPH:protochlorophyllide oxidoreductase (POR) is the key enzyme for light-dependent chlorophyll biosynthesis. It accumulates in dark-grown plants as the ternary enzyme-substrate complex POR-protochlorophyllide a-NADPH. Here, we describe a
Publikováno v:
Biochimica et Biophysica Acta (BBA) - Bioenergetics. 1410:262-272
[8-vinyl]-Protochlorophyllide a1The nomenclature for chlorophylls is somewhat confusing: [8-vinyl]-protochlorophyllide was known as Mg-2,4-divinyl-pheoporphyrin a5-monomethyl ester (old Fischer nomenclature). We prefer the name divinyl-protochlorophy
Publikováno v:
Journal of Biological Chemistry. 271:32174-32179
Stabilization of chlorophyll a-binding apoproteins P700, CP47, CP43, D2, and D1 against proteolytic degradation has been investigated through in vitro synthesis of chlorophyll a or Zn-pheophytin a in intact etioplasts from barley. Stabilization of th
Publikováno v:
Zeitschrift für Naturforschung C. 51:185-194
The chemical reduction of the formyl group of pheophorbide b with sodium cyanoborohy dride in methanol leads to 71-methoxy-and 71-hydroxy-pheophorbide a. The same reaction with zinc pheophorbide b yields in addition zinc pheophorbide a. This was ch
Publikováno v:
Journal of the American Chemical Society. 118:2606-2611
Protochlorophyllide a was isolated from dark-grown barley (Hordeum vulgare L.) seedlings. The circular dichroism spectrum was identical with that of protochlorophyll a prepared from chlorophyll a b...
Autor:
Christer Sundqvist, Wolfhart Rüdiger, Siegrid Schoch, Margareta Ryberg, Michael Helfrich, Bengt Wiktorsson
Publikováno v:
European Journal of Biochemistry. 229:291-298
A preparation of prolamellar bodies from wheat etioplasts was used as a source for NADPH-protochlorophyllide oxidoreductase (pchlide reductase). The enzyme was solubilized with Triton X-100 after reduction of the endogenous photoconvertible protochlo
Autor:
Wolfhart Rüdiger, Michael Helfrich
Publikováno v:
Zeitschrift für Naturforschung C. 47:231-238
Pheophorbide a was prepared from a mixture of chlorophylls a and b by differential extraction with HCl and saponification. The insertion of the following metal ions was investigated: Mg, Zn, Co, Cu, Ni. In the enzyme test with chlorophyll synthetase,
Publikováno v:
Biochemistry. 44(32)
Enzymes catalyzing two of the late steps of chlorophyll biosynthesis are NADPH:protochlorophyllide oxidoreductase (POR), responsible for the light-dependent reduction of protochlorophyllide to chlorophyllide, and chlorophyll synthase that catalyses t