The functional and molecular characterisation of the pig ileal NA+/bile acid co-transport protein

2.50
Hdl Handle:
http://hdl.handle.net/10547/622137
Title:
The functional and molecular characterisation of the pig ileal NA+/bile acid co-transport protein
Authors:
Knight, Gillian Lynsey
Abstract:
Bile acids are essential for the efficient digestion and absorption of lipids, and are re-absorbed by aNa+ /bile acid co-transport protein within the ileum. Investigation into the transport protein, using BBMV and Xenopus laevis oocytes, revealed that pig ileal Na +/bile acid co-transport protein was not strictly dependent of the presence of an inwardly directed Na + gradient, as previously determined. Cations which had ionic radii between 0.8 - 1.33A, most notably Na+, K+ and Ca2+, stimulated secondary active transport of taurocholate. Taurocholate uptake in the presence of inwardly directed cation gradients of Na + and K+, demonstrated Michealis Menten Kinetics, concentrative accumulation, competitive inhibition and was temperature sensitive. Preventing the translation of the gene encoding the Na+/bile acid co-transport protein, abolished secondary active transport in the presence ofboth Na+ and K+. Isolation and computer modelling of the gene which encoded the pig ileal Na +/bile acid co-transport protein, revealed that this protein was composed of 8 transmembrane domains and lead to the identification of proposed cation and bile acid binding sites. The ability of K+ to stimulate the Na +/bile acid co-transport protein could be of physiological importance in vivo, because of the depleted Na + concentration present within the ileum. Though, the rate of taurocholate transport in the presence of K+ is reduced when compared to Na+, the transport protein has very similar affinities for taurocholate in the presence of both cations and therefore could use K+ for efficient re-absorption of taurocholate. Therefore, for this study it was proposed that the Na+/bile acid co-transport protein had a preference for Na+ rather than a strict dependence as previously concluded.
Citation:
Knight, G.L. (2000) 'The functional and molecular characterisation of the pig ileal NA+/bile acid co-transport protein'. PhD thesis. University of Luton.
Publisher:
University of Bedfordshire
Issue Date:
Dec-2000
URI:
http://hdl.handle.net/10547/622137
Type:
Thesis or dissertation
Language:
en
Appears in Collections:
PhD e-theses

Full metadata record

DC FieldValue Language
dc.contributor.authorKnight, Gillian Lynseyen
dc.date.accessioned2017-06-30T11:03:59Z-
dc.date.available2017-06-30T11:03:59Z-
dc.date.issued2000-12-
dc.identifier.citationKnight, G.L. (2000) 'The functional and molecular characterisation of the pig ileal NA+/bile acid co-transport protein'. PhD thesis. University of Luton.en
dc.identifier.urihttp://hdl.handle.net/10547/622137-
dc.description.abstractBile acids are essential for the efficient digestion and absorption of lipids, and are re-absorbed by aNa+ /bile acid co-transport protein within the ileum. Investigation into the transport protein, using BBMV and Xenopus laevis oocytes, revealed that pig ileal Na +/bile acid co-transport protein was not strictly dependent of the presence of an inwardly directed Na + gradient, as previously determined. Cations which had ionic radii between 0.8 - 1.33A, most notably Na+, K+ and Ca2+, stimulated secondary active transport of taurocholate. Taurocholate uptake in the presence of inwardly directed cation gradients of Na + and K+, demonstrated Michealis Menten Kinetics, concentrative accumulation, competitive inhibition and was temperature sensitive. Preventing the translation of the gene encoding the Na+/bile acid co-transport protein, abolished secondary active transport in the presence ofboth Na+ and K+. Isolation and computer modelling of the gene which encoded the pig ileal Na +/bile acid co-transport protein, revealed that this protein was composed of 8 transmembrane domains and lead to the identification of proposed cation and bile acid binding sites. The ability of K+ to stimulate the Na +/bile acid co-transport protein could be of physiological importance in vivo, because of the depleted Na + concentration present within the ileum. Though, the rate of taurocholate transport in the presence of K+ is reduced when compared to Na+, the transport protein has very similar affinities for taurocholate in the presence of both cations and therefore could use K+ for efficient re-absorption of taurocholate. Therefore, for this study it was proposed that the Na+/bile acid co-transport protein had a preference for Na+ rather than a strict dependence as previously concluded.en
dc.language.isoenen
dc.publisherUniversity of Bedfordshireen
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/*
dc.subjectbile aciden
dc.subjectproteinsen
dc.subjectC700 Molecular Biology, Biophysics and Biochemistryen
dc.titleThe functional and molecular characterisation of the pig ileal NA+/bile acid co-transport proteinen
dc.typeThesis or dissertationen
dc.type.qualificationnamePhDen_GB
dc.type.qualificationlevelPhDen
dc.publisher.institutionUniversity of Bedfordshireen
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