Field-dispersion profiles of the proton spin-lattice relaxation rate in chloroplast suspensions. Effect of manganese extraction by EDTA, Tris, and hydroxylamine
dc.contributor.author | Sharp, Robert R. | en_US |
dc.contributor.author | Yocum, Charles F. | en_US |
dc.date.accessioned | 2006-04-07T17:22:27Z | |
dc.date.available | 2006-04-07T17:22:27Z | |
dc.date.issued | 1980-08-05 | en_US |
dc.identifier.citation | Sharp, Robert R., Yocum, C. F. (1980/08/05)."Field-dispersion profiles of the proton spin-lattice relaxation rate in chloroplast suspensions. Effect of manganese extraction by EDTA, Tris, and hydroxylamine." Biochimica et Biophysica Acta (BBA) - Bioenergetics 592(1): 185-195. <http://hdl.handle.net/2027.42/23172> | en_US |
dc.identifier.uri | http://www.sciencedirect.com/science/article/B6T1S-47RS7WB-1B/2/730069089826a9ebb3def9b5e4fcfd7b | en_US |
dc.identifier.uri | https://hdl.handle.net/2027.42/23172 | |
dc.identifier.uri | http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=retrieve&db=pubmed&list_uids=6249353&dopt=citation | en_US |
dc.description.abstract | Proton spin-lattice relaxation rates (R1) have been measured in a variety of dark-adapted chloroplast suspensions over a range of field strengths between 1 and 15 kG (4-5 MHz). When the effects of EDTA or Tris washing on chloroplast relaxivities are compared, the pool of Mn associated with oxygen evolution is seen not to contribute significantly to relaxivity. Instead, nearly all of the observed relaxivity, which is characterized by a paramagnetic maximum near 20.7 MHz in the field dispersion profile of R1, appears to arise from contaminating non-functional Mn(II) that can be removed by EDTA during the isolation procedure. These observations, which contradict previous reports ascribing chloroplast relaxivity to the water-oxidizing system, require a reevaluation of proposed models, derived from NMR studies, of the state of Mn in the water-splitting reaction.Chloroplasts from which loosely bound non-functional Mn has been removed by EDTA washing do show an enhancement of relaxivity when exposed to NH2OH at concentrations known to inactivate water oxidation. This NH2OH-induced relaxivity is comprised of Mn(II) in two distinct paramagnetic sites. One site is chelatable by EDTA, whereas the other site is not. This finding suggests that some Mn(II) tightly bound to thylakoid membranes can contribute to relaxivity after inactivation of the oxygen-evolving reaction. | en_US |
dc.format.extent | 758353 bytes | |
dc.format.extent | 3118 bytes | |
dc.format.mimetype | application/pdf | |
dc.format.mimetype | text/plain | |
dc.language.iso | en_US | |
dc.publisher | Elsevier | en_US |
dc.title | Field-dispersion profiles of the proton spin-lattice relaxation rate in chloroplast suspensions. Effect of manganese extraction by EDTA, Tris, and hydroxylamine | en_US |
dc.type | Article | en_US |
dc.rights.robots | IndexNoFollow | en_US |
dc.subject.hlbsecondlevel | Materials Science and Engineering | en_US |
dc.subject.hlbsecondlevel | Chemistry | en_US |
dc.subject.hlbsecondlevel | Chemical Engineering | en_US |
dc.subject.hlbtoplevel | Science | en_US |
dc.subject.hlbtoplevel | Engineering | en_US |
dc.description.peerreviewed | Peer Reviewed | en_US |
dc.contributor.affiliationum | Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109, U.S.A. | en_US |
dc.contributor.affiliationum | Division of Biological Sciences, The University of Michigan, Ann Arbor, MI 48109, U.S.A.; Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109, U.S.A. | en_US |
dc.identifier.pmid | 6249353 | en_US |
dc.description.bitstreamurl | http://deepblue.lib.umich.edu/bitstream/2027.42/23172/1/0000097.pdf | en_US |
dc.identifier.doi | http://dx.doi.org/10.1016/0005-2728(80)90124-3 | en_US |
dc.identifier.source | Biochimica et Biophysica Acta | en_US |
dc.owningcollname | Interdisciplinary and Peer-Reviewed |
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