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DC Field | Value | Language |
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dc.citation.endPage | 857 | - |
dc.citation.number | 6 | - |
dc.citation.startPage | 854 | - |
dc.citation.title | PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY | - |
dc.citation.volume | 436 | - |
dc.contributor.author | Matskevitch, J | - |
dc.contributor.author | Wagner, CA | - |
dc.contributor.author | Risler, T | - |
dc.contributor.author | Kwon, H. Moo | - |
dc.contributor.author | Handler, JS | - |
dc.contributor.author | Waldegger, S | - |
dc.contributor.author | Busch, AE | - |
dc.contributor.author | Lang, F | - |
dc.date.accessioned | 2023-12-22T12:14:02Z | - |
dc.date.available | 2023-12-22T12:14:02Z | - |
dc.date.created | 2014-05-22 | - |
dc.date.issued | 1998-11 | - |
dc.description.abstract | The myo-inositol transporter SMIT is expressed particularly at high extracellular osmolarity and serves to accumulate the osmolyte myo-inositol. Transport of myo-inositol is coupled to the cotransport of Na+ and is electrogenic. In Xenopus oocytes injected with mRNA encoding SMIT but not in water-injected oocytes, myo-inositol creates an inward current that is dependent on the ambient Na+ concentration. The present study has been performed to elucidate the pH dependence of myo-inositol-induced currents. Therefore, Xenopus oocytes were injected with mRNA encoding SMIT and two-electrode voltage-clamp studies were performed. The myo-inositol-induced currents in oocytes expressing SMIT were found to have a sigmoidal dependence on the ambient pH between pH 5.5 and 8.5 with an apparent K-i of 0.21+/-001 mu M H+ and a Hill coefficient of 1.80+/-0.16. Kinetic analysis of the myo-inositol-induced currents at pH 8.0 and -90 mV holding potential revealed a Hill coefficient of 0.93+/0.07 and an apparent K-m, for myo-inositol of 0.031+/-0.003 mM as well as a Hill coefficient of 1.64+/-0.24 and an apparent K-m of 38.8+/-4.1 mM for Na+. A decrease of the Na+ concentration from 150 mM to 50 mM significantly altered the maximal observed current and increased the apparent K-m for myo-inositol. Acidification to pH 6.5 significantly increased the apparent K-m for myo-inositol and for Na+ to 0.057+/-0.005 mM and 73.9+/-4.8 mM, respectively. The Hill coefficients for myo-inositol and Na+ were not affected and remained close to 1 for myo-inositol and 2 for Na+. In summary, acidification impedes SMIT-mediated myo-inositol transport at least partially by decreasing the affinity of the carrier for Na+. The impaired Na+ binding subsequently decreases binding and transport of myo-inositol. | - |
dc.identifier.bibliographicCitation | PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY, v.436, no.6, pp.854 - 857 | - |
dc.identifier.doi | 10.1007/s004240050714 | - |
dc.identifier.issn | 0031-6768 | - |
dc.identifier.scopusid | 2-s2.0-0031733739 | - |
dc.identifier.uri | https://scholarworks.unist.ac.kr/handle/201301/4731 | - |
dc.identifier.url | http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=0031733739 | - |
dc.identifier.wosid | 000076668700006 | - |
dc.language | 영어 | - |
dc.publisher | SPRINGER | - |
dc.title | Effect of extracellular pH on the myo-inositol transporter SMIT expressed in Xenopus oocytes | - |
dc.type | Article | - |
dc.description.journalRegisteredClass | scopus | - |
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