ArticleThe Biochemical journal1993
Folate transport in intestinal brush border membrane: involvement of essential histidine residue(s).
Article in The Biochemical journal, 1993. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 3 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
3 citing papers in PubMed, 22 citations in OpenAlex.
- Riboflavin transport and metabolism in humans.Journal of inherited metabolic disease · 2016Review
- The functional roles of the His247 and His281 residues in folate and proton translocation mediated by the human proton-coupled folate transporter SLC46A1.The Journal of biological chemistry · 2009Article
- Biophysical evidence for His57 as a proton-binding site in the mammalian intestinal transporter hPepT1.Pharmaceutical research · 2003Article
Corrections and comments
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Authors and funding
2 authors at 2 institutions in 1 country.
Funding
Abstract
We examined the possible existence of histidine residue(s) in the folate transporter of rabbit intestine. This was done with use of the histidine-specific reagent diethyl pyrocarbonate (DEPC) and purified intestinal brush-border-membrane vesicles. DEPC caused significant concentration- and time-dependent inhibition of folic acid transport. The inhibition was only seen when transport was examined in vesicles incubated in buffer at pH 5.2 and not in those incubated in buffer at pH 7.4. The addition of unlabelled folic acid to vesicle suspension before treatment with DEPC (2.5 mM) led to a significant (P < 0.01) protection (84%) against the inhibition of folic acid transport. Treating vesicles pretreated with DEPC (2.5 mM) with reducing reagents (dithiothreitol, 2-mercaptoethanol and 2,3-dimercaptopropanol, all at a final concentration of 10 mM) did not reverse the inhibitory effect of DEPC on folic acid transport. On the other hand, treating the DEPC-pretreated vesicles with hydroxylamine (140 mM) led to a significant reversal (P < 0.01) (54%) of the inhibition of folic acid transport. The inhibitory effect of DEPC on carrier-mediated folic acid transport was found to be mediated through a decrease in the Vmax. (i.e. a decrease in the number and/or activity) of the carriers and an increase in the apparent Km (i.e. a decrease in their affinity), classifying the effect as a mixed-type inhibition. These results demonstrate the existence of critical histidine residue(s) in the intestinal brush-border-membrane folate transporter which is essential for its interaction with, and transport of, the vitamin. These findings also suggest that the histidine residue(s) is located at (or near) the substrate-binding site.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.