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dc.contributor.authorHandlogten, Mary E.en_US
dc.contributor.authorChristensen, Halvor N.en_US
dc.date.accessioned2006-09-11T19:40:27Z
dc.date.available2006-09-11T19:40:27Z
dc.date.issued1977-12en_US
dc.identifier.citationChristensen, Halvor N.; Handlogten, Mary E.; (1977). "Na + /L + selectivity in transport system A : Effects of substrate structure." The Journal of Membrane Biology 37(1): 193-211. <http://hdl.handle.net/2027.42/48026>en_US
dc.identifier.issn0022-2631en_US
dc.identifier.issn1432-1424en_US
dc.identifier.urihttps://hdl.handle.net/2027.42/48026
dc.identifier.urihttp://www.ncbi.nlm.nih.gov/sites/entrez?cmd=retrieve&db=pubmed&list_uids=563921&dopt=citationen_US
dc.description.abstractThe effect of amino acid structure on the selectivity between Na and Li as co-substrates for transport System A in the Ehrlich cell has been explored to localize relative binding positions. By various tests the relative effectiveness of the two cations varies over fivefold. Changes in structure of the amino acid that lower its response to Na tend to decrease its selectivity for Na over Li, but with many exceptions. The higher the Li level required to half-maximize amino acid entry, the slower tends to be the entry attainable for both Li and amino acid. Our attention fell on strong departures from these trends. An atypically fast uptake is produced by Li in the presence of a second amino group pK′ 2 <8.5, in exceptional association with the known fast uptake in Na. The hydroxyl group of serine yields exceptionally strong uptake, whereas hydroxyl groups in restrained orientation (as in threonine and hydroxyprolines) sharply limit co-substrate interaction. Despite the absence of a sidechain, glycine shows unexceptional relative co-substrate responses. A sidechain in the α 2 position, as in d -alanine, lowers tolerance for both ions, an aberration largely corrected by the insertion of a second (α 2 ) methyl group, and surprisingly, even by an N-methyl group. For l -alanine, an N-methyl group has in contrast unfavorable effects on co-substrate interaction. These factors point to disturbance by the α 2 methyl group of the position taken by the amino acid at the site, largely rectifiable by balancing effects of a second methyl group. They also point to a position of the alkali ion quite close to the α-carbon and far from the position taken in System ASC . Addition of an ethylene bridge between the α-methyl groups of α(methylamino)-isobutyric acid leads to the strongest discrimination seen against Li + relative to Na + , suggesting through crowding of the area that the alkali ion adjoins the three methyl groups of this analog.en_US
dc.format.extent1080887 bytes
dc.format.extent3115 bytes
dc.format.mimetypeapplication/pdf
dc.format.mimetypetext/plain
dc.language.isoen_US
dc.publisherSpringer-Verlag; Springer-Verlag New York Inc.en_US
dc.subject.otherHuman Physiologyen_US
dc.subject.otherLife Sciencesen_US
dc.subject.otherBiochemistry, Generalen_US
dc.titleNa + /L + selectivity in transport system A : Effects of substrate structureen_US
dc.typeArticleen_US
dc.subject.hlbsecondlevelMolecular, Cellular and Developmental Biologyen_US
dc.subject.hlbsecondlevelGeneticsen_US
dc.subject.hlbtoplevelScienceen_US
dc.subject.hlbtoplevelHealth Sciencesen_US
dc.description.peerreviewedPeer Revieweden_US
dc.contributor.affiliationumDepartment of Biological Chemistry, The University of Michigan, 48109, Ann Arbor, Michiganen_US
dc.contributor.affiliationumDepartment of Biological Chemistry, The University of Michigan, 48109, Ann Arbor, Michiganen_US
dc.contributor.affiliationumcampusAnn Arboren_US
dc.identifier.pmid563921en_US
dc.description.bitstreamurlhttp://deepblue.lib.umich.edu/bitstream/2027.42/48026/1/232_2005_Article_BF01940932.pdfen_US
dc.identifier.doihttp://dx.doi.org/10.1007/BF01940932en_US
dc.identifier.sourceThe Journal of Membrane Biologyen_US
dc.owningcollnameInterdisciplinary and Peer-Reviewed


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