Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A Scatchard plot for the strongly bound Eu3+ to deionized bacteriorhodopsin (bR) was made using a method based on measuring the concentration of unbound Eu3+ from its fluorescence intensity. The results suggest that the first mole of Eu3+ added to a mole of bR is strongly bound by displacing 2-3 protons. In order to reconcile this result with the previous time-resolved fluorescence studies on Eu(3+)-regenerated bR, which showed the presence of 3 sites of comparable binding constants, one is forced to conclude that the emission from the strongly bound Eu3+ is completely quenched, e.g. by energy transfer to the retinal. For this to take place, the Eu3+ must be within a few A from the retinal, i.e. within the retinal pocket (the active site). The possible importance of this conclusion to the deprotonation mechanism of the protonated Schiff base, the switch of the proton pump in bR, is discussed.
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PMID:The binding site of the strongly bound Eu3+ in Eu(3+)-regenerated bacteriorhodopsin. 203 59

Venous malformations of blue rubber bleb nevus syndrome (BRBNS) may involve any area of the gastrointestinal tract. Gastrointestinal blood loss and anemia brings these patients to the attention of gastroenterologists. Effective treatment of these malformations throughout the gastrointestinal tract requires aggressive management to ultimately decrease blood loss and restore the patient's hemoglobin to a near-normal level. Treatment of patients with BRBNS includes supportive measures, endoscopic ablation, and surgery. Supportive therapy consists of proton pump inhibitors and octreotide to decrease blood loss, iron replacement, and blood transfusions. The effective management of patients with anemia demands aggressive treatment of venous malformations in the small bowel. This requires a collaboration between the surgeon and the therapeutic endoscopist, ie, laparotomy and excision of larger lesions with surgically assisted enteroscopy and thermal ablation of smaller lesions via enterotomy. There is no effective systemic therapy for treatment of the vascular malformations in patients with BRBNS.
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PMID:Blue Rubber Bleb Nevus Syndrome. 1156 Jul 90

Restoration of acid secretion after treatment with covalently-bound proton pump inhibitors may depend on protein turnover and on reversal of inhibition by reducing agents such as glutathione. Glutathione incubation of the H(+),K(+)-ATPase isolated from omeprazole or pantoprazole-treated rats reversed 88% of the omeprazole inhibition but none of the pantoprazole inhibition. The present study was designed to measure binding properties of omeprazole or pantoprazole in vivo. Rats were injected with (14)C-omeprazole or (14)C-pantoprazole after acid stimulation. The specific binding to the gastric H(+),K(+)-ATPase was measured at timed intervals as well as reversal of binding by glutathione reduction. The stoichiometry of omeprazole and pantoprazole binding to the catalytic subunit of the H(+),K(+)-ATPase was 2 moles of inhibitor per mole of the H(+),K(+)-ATPase phosphoenzyme. Omeprazole bound to one cysteine between transmembrane segments 5/6 and one between 7/8, pantoprazole only to the two cysteines in the TM5/6 domain. Loss of drug from the pump was biphasic, the fast component accounted for 84% of omeprazole binding and 51% of pantoprazole binding. Similarly, only 16% of omeprazole binding but 40% of pantoprazole binding was not reversed by glutathione. The residence time of omeprazole and pantoprazole on the ATPase in vivo depends on the reversibility of binding. Binding of pantoprazole at cysteine 822 is irreversible whereas that of omeprazole at cysteine 813 and 892 is reversible both in vivo and in vitro. This is consistent with the luminal exposure of cysteine 813 and 892 and the intra-membranal location of cysteine 822 in the 3D structure of the H(+),K(+)-ATPase.
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PMID:Differences in binding properties of two proton pump inhibitors on the gastric H+,K+-ATPase in vivo. 1549 2

The utilization of HCO(3) (-) as carbon source for photosynthesis by aquatic angiosperms results in the production of 1 mole OH(-) for each mole CO(2) assimilated. The OH(-) ions are subsequently released to the medium. In several Potamogeton and Elodea species, the site of the HCO(3) (-) influx and OH(-) efflux are spatially separated. Described here are light- and dark-induced pH changes at the lower and upper epidermis of the leaves of Potamogeton lucens, Elodea densa, and Elodea canadensis.In the light, two phases could be discerned. During the first phase, the pH increased at both sides of the leaves. This pH increase apparently resulted from CO(2) fixation. During the second, so-called polar phase, the pH at the upper side increased further, but the pH at the lower side dropped below the pH of the ambient solution. The pH drop at the lower epidermis indicates that the K(+) influx exceeds the net CO(2) (HCO(3) (-) + CO(2)) influx slightly. This may result either from a proton pump driving an extra K(+) influx or from CO(2) diffusion from the cells into the outer medium previously taken up as HCO(3) (-). In the dark, a CO(2) gush was observed at both sides. During the polar phase, the upper side becomes electrically negative with respect to the lower side. Subsequent depolarization in the dark revealed that this potential difference consisted of a fast and a slow component.
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PMID:Photosynthetic HCO(3) Utilization and OH Excretion in Aquatic Angiosperms: LIGHT-INDUCED pH CHANGES AT THE LEAF SURFACE. 1666 33