The glucose-6-phosphate transport is not mediated by a glucose-6-phosphate/phosphate exchange in liver microsomes
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- 作者：Paola Marcolongo ; Rosella Fulceri ; Roberta Giunti ; Eva Margittai ; Gabor Banhegyi ; Angelo Benedetti
- 关键词：G6PT ; glucose-6-phosphate transporter ; G6P ; glucose-6-phosphate ; ER ; endoplasmic reticulum ; Pi ; inorganic phosphate ; G6Pase ; glucose-6-phosphatase ; H6PD ; hexose-6-phosphate dehydrogenase ; DIDS ; 4 ; 4&prime ; -diisothiocyanostilbene-2 ; 2&prime ; -disulfonic acid
- 刊名：FEBS Letters
- 出版年：2012
- 出版时间：21 September, 2012
- 年：2012
- 卷：586
- 期：19
- 页码：3354-3359
- 全文大小：576 K
文摘
A phosphate-linked antiporter activity of the glucose-6-phosphate transporter (G6PT) has been recently described in liposomes including the reconstituded transporter protein. We directly investigated the mechanism of glucose-6-phosphate (G6P) transport in rat liver microsomal vesicles. Pre-loading with inorganic phosphate (Pi) did not stimulate G6P or Pi microsomal inward transport. Pi efflux from pre-loaded microsomes could not be enhanced by G6P or Pi addition. Rapid G6P or Pi influx was registered by light-scattering in microsomes not containing G6P or Pi. The G6PT inhibitor, S3483, blocked G6P transport irrespectively of experimental conditions. We conclude that hepatic G6PT functions as an uniporter.