Abstract:
:Gastric parietal cell apical membranes must protect the cell from the extremely low pH and wide variations in osmolality of the gastric juice. To characterize the permeability properties of gastric apical membranes, we have measured passive permeabilities to water, protons, NH3, and small nonelectrolytes of membrane vesicles derived from parietal cells of fasted animals and fed animals. Both preparations are known to be highly enriched in H+/K(+)-ATPase, the enzyme responsible for acidifying the gastric contents. The preparations behaved as single populations, and their permeability properties were similar in all respects, permitting pooling of the results. This similarity suggests that insertion of tubulovesicles into the apical membrane does not change the behavior of the lipid bilayer. Osmotic water permeability (Pf) averaged (mean +/- SD) (2.8 +/- 0.3) x 10(-4) cm/s, a value 10-fold lower than that obtained in lecithin large unilamellar vesicles (LUV) and similar to that obtained in other water-tight epithelia. Similarly, ammonia permeability (PNH3) was low [(4.4 +/- 2.3) x 10(-3) cm/s] and 10 times below that of lecithin LUV. By contrast, proton permeability (PH+) was surprisingly high (0.030 +/- 0.011 cm/s) and similar to that of lecithin LUV. These results suggest that the pathway for proton permeation differs from that of water and NH3. Nonelectrolyte permeabilities were strikingly similar to those obtained in another water-tight epithelium, the toad urinary bladder. Moreover, these permeabilities followed Overton's rule in that permeability varied in accordance with the oil-water partition coefficient. We conclude that the gastric apical membrane, like that of several renal epithelia, is relatively water-tight and exhibits low permeabilities to small nonelectrolytes. These properties are likely to be essential to the ability of this membrane to perform its barrier function.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Priver NA,Rabon EC,Zeidel MLdoi
10.1021/bi00061a002subject
Has Abstractpub_date
1993-03-16 00:00:00pages
2459-68issue
10eissn
0006-2960issn
1520-4995journal_volume
32pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::Voltage-dependent anion channel 1 (VDAC1) situated in the outer mitochondrial membrane regulates the transfer of various metabolites and is a key player in mitochondria-mediated apoptosis. Although many small chemicals that modulate the functions of VDAC1 have been reported to date, most, if not all, of them cannot be...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.8b01209
更新日期:2019-02-26 00:00:00
abstract::Living organisms have evolved a vast array of catalytic functions that make them ideally suited for the production of medicinally and industrially relevant small-molecule targets. Indeed, native metabolic pathways in microbial hosts have long been exploited and optimized for the scalable production of both fine and co...
journal_title:Biochemistry
pub_type: 杂志文章,评审
doi:10.1021/bi200416g
更新日期:2011-06-21 00:00:00
abstract::The clam Scapharca inaequivalvis possesses two cooperative oxygen binding hemoglobins in its red cells: a homodimeric HbI and a heterotetrameric A2B2 HbII. Each AB dimeric half of HbII is assembled in a manner very similar to that of the well-studied HbI. This study presents crystal structures of HbII along with oxyge...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi301620x
更新日期:2013-03-26 00:00:00
abstract::Clustering of anionic lipids away from zwitterionic ones by cationic antimicrobial agents has recently been established as a mechanism of action of natural small, flexible peptides as well as non-natural synthetic peptide mimics. One of the largest classes of antimicrobial peptides consists of peptides that form catio...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi100378m
更新日期:2010-05-18 00:00:00
abstract::The acid-induced denaturation of barnase and its mutants has been analyzed to search for partly-folded intermediates. Differential scanning calorimetry of barnase deviates from two-state behavior below pH 4.0 at low ionic strength, with the maximum discrepancy at pH 2.7. Addition of 200 mM KCl apparently restores the ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00203a015
更新日期:1994-09-20 00:00:00
abstract::Oligodeoxynucleotides modified site-specifically with dG-(+)-trans- and dG-(+)-cis-anti-BPDE (7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene) or dG-(-)-trans- and dG-(-)-cis-anti-BPDE were used as templates in primer extension reactions catalyzed by the Klenow fragment of Escherichia coli DNA polymerase I....
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00080a027
更新日期:1993-07-27 00:00:00
abstract::Phosphorescence from the lone tryptophan residue has been studied to monitor the interaction of myelin basic protein with phosphatidylserine vesicles. Spectral shifts in the phosphorescence of the protein in a glycerol-buffer (70:30 w/w) solvent at low temperature are consistent with fluorescence data obtained under a...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00514a019
更新日期:1981-05-26 00:00:00
abstract::Phospholipase A(2) (PLA(2)) (E. C. 3.1.1.4) is a common enzyme in the two-way cascade mechanism leading to the production of proinflammatory compounds known as eicosanoids. The binding of phospholipase A(2) to the membrane surface and hydrolysis of phospholipids are thought to involve the formation of a hydrophobic ch...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi035076x
更新日期:2003-10-14 00:00:00
abstract::Three tyrosine-to-phenylalanine mutants of ribonuclease A (Y25F, Y92F, and Y97F) are investigated for their enzymatic activities, molecular stabilities, and unfolding/refolding kinetics. These mutants exhibit 80, 90, and 80%, respectively, of the catalytic activity of the wild-type enzyme. Thermal, Gdn.HCl, and pH tra...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi970711i
更新日期:1997-08-19 00:00:00
abstract::The functional interaction of the recombinant alpha 2 adrenergic receptor subtypes, alpha 2-C10 (the human platelet alpha 2 receptor, equivalent to the alpha 2 A subtype) and alpha 2-C4 (an alpha 2 receptor subtype cloned from a human kidney cDNA library), with G proteins was characterized in an in vitro reconstitutio...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00227a024
更新日期:1991-04-02 00:00:00
abstract::DNA gyrase is the target of a number of antibacterial agents, including the coumarins and the cyclothialidines. To extend our understanding of the mechanism of action of these compounds, we have examined the previously published crystal structures of the complexes between the 24 kDa fragment of GyrB and coumarin and c...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi982320p
更新日期:1999-02-16 00:00:00
abstract::The dimeric nature of the HIV protease has been exploited to devise a novel mode of inhibiting the enzyme. The use of defective monomers or nonidentical subunits to exchange with wild-type homodimers produces catalytically defective heterodimers. Incubation of the HIV1 or HIV2 protease with a 4-fold molar excess of an...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00215a016
更新日期:1991-01-08 00:00:00
abstract::Fluorescence recovery after photobleaching was used to measure the diffusion coefficient of green fluorescent protein (GFP, 27 kDa) in Escherichia coli in the presence or absence of four coexpressed proteins: cytoplasmic maltose binding protein (42 kDa), tau-40 (45 kDa), alpha-synuclein (14 kDa), or calmodulin (17 kDa...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9004107
更新日期:2009-06-16 00:00:00
abstract::Solutions of porcine lactate dehydrogenase of micromolar concentration kept at 4 degrees C for several days lose the greater part of their enzymic activity but recover it when returned to room temperature. The rate of spoiling decreases and the rate of recovery increases with the concentration of the solutions. The de...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00360a024
更新日期:1986-06-17 00:00:00
abstract::The structure of premature core enzyme, an obligatory intermediate in both in vivo and in vitro assembly of Escherichia coli DNA-dependent RNA polymerase, was compared with that of native core enzyme. Though this assembled but inactive form of core enzyme harbors the gross conformation similar to that of native enzyme...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00573a006
更新日期:1979-03-20 00:00:00
abstract::The baker's yeast saccharopine dehydrogenase (EC 1.5.1.7) was inactivated by 2,3-butanedione following pseudo-first-order reaction kinetics. The pseudo-first-order rate constant for inactivation was linearly related to the butanedione concentration, and a value of 7.5 M-1 min-1 was obtained for the second-order rate c...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00506a004
更新日期:1981-02-03 00:00:00
abstract::The bacterial alpha-lytic protease (alphaLP) is synthesized as a precursor containing a large N-terminal pro region (Pro) transiently required for correct folding of the protease [Silen, J. L., and Agard, D. A. (1989) Nature 341, 462-464]. Upon folding, the precursor is autocatalyticly cleaved to yield a tight-binding...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi982165e
更新日期:1999-04-13 00:00:00
abstract::The contributions to thermostability of interactions within the beta-sheet region of rubredoxins (Rds) were investigated by examining proteins in which beta-strand sequences of Rds from the hyperthermophilic archaeon Pyrococcus furiosus (Pf) and the mesophilic bacterium Clostridium pasteurianum (Cp) were interchanged....
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi970110r
更新日期:1997-08-26 00:00:00
abstract::Isoelectrofocusing gels of acidic ribosomal proteins from most yeast strains reveal the presence of up to 10 bands which are the product of only 4 genes. The proteins have been characterized by NH2-terminal amino acid sequencing, specific antibodies, HPLC, and by taking advantage of acidic protein-defective yeast stra...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00067a010
更新日期:1993-04-27 00:00:00
abstract::A new series of negatively charged, paramagnetic alkylsulfonate probes was synthesized and can be used to measure both the internal and the external surface potentials of model membrane systems. We tested for discreteness-of-charge effects in lipid membranes by comparing the surface potentials, estimated by use of the...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00373a014
更新日期:1986-12-16 00:00:00
abstract::A new procedure for the synthesis of the pyrophosphate bond has been employed in the preparation of nucleoside dipyrophosphates from nucleoside 3',5'-diphosphates. The method makes use of a powerful phosphorylating agent generated in a mixture of cyanoethyl phosphate, dicyclohexylcarbodiimide, and mesitylenesulfonyl c...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00666a012
更新日期:1976-10-19 00:00:00
abstract::Genetic knockout of the BtR4 gene encoding the Heliothis virescens cadherin-like protein (HevCaLP) is linked to resistance against Cry1Ac toxin from Bacillus thuringiensis. However, the functional Cry1Ac receptor role of this protein has not been established. We previously proposed HevCaLP as a shared binding site for...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0606703
更新日期:2006-08-15 00:00:00
abstract::Drug intervention that prevents reabsorption of circulating bile acids by the apical (ileal) sodium/bile acid cotransporter (ASBT) may be a promising new therapy for lowering of plasma cholesterol. 2164U90 is a benzothiazepine-based competitive inhibitor of bile acid transport with K(i) values of approximately 10 and ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0205404
更新日期:2002-12-17 00:00:00
abstract::"Sequence-dictated" scission of DNA can be achieved by tethering a fusion protein composed of glutathione S-transferase and attenuated micrococcal nuclease (MN) to a targeting oligonucleotide using Cibacron blue (CB) F3G-A. Deoxyoligonucleotides derivatized with this dye bind to the fusion protein in gel mobility shif...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00201a006
更新日期:1994-09-06 00:00:00
abstract::Peptide deformylase (EC 3.5.1.31) catalyzes the removal of a formyl group from the N-termini of nascent ribosome-synthesized polypeptides, an obligatory step during protein maturation in eubacteria. Since its discovery in crude Escherichia coli extracts 3 decades ago, the deformylase has resisted all attempts of purif...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi971155v
更新日期:1997-11-11 00:00:00
abstract::The human endonuclease III homologue (hNTH1) removes premutagenic cytosine damage from DNA. This includes 5-hydroxycytosine, which has increased potential for pairing with adenine, resulting in C --> T transition mutations. Here we report that hNTH1 acts on both 5-hydroxycytosine and abasic sites preferentially when t...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0028901
更新日期:2001-06-05 00:00:00
abstract::Isolation and characterization of a novel radiation-induced product, i.e., the 8-hydroxyguanine residue, produced in deoxyribonucleic acid (DNA), 2'-deoxyguanosine, and 2'-deoxyguanosine 5'-monophosphate by gamma-irradiation in aqueous solution, are described. For this purpose, gamma-irradiated DNA was first hydrolyze...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00337a032
更新日期:1985-07-30 00:00:00
abstract::Circular dichroism spectra of the partially folded trapped intermediates were measured in order to aid in the elucidation of the conformational forces which determine a nonrandom, nonsequential pathway of disulfide bond formation upon refolding of bovine pancreatic trypsin inhibitor. Whatever conformation was responsi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00279a020
更新日期:1983-05-10 00:00:00
abstract::Epitranscriptomic RNA modifications can serve as recognition elements for the recruitment of effector proteins (i.e., "readers") to modified transcripts. While these interactions play an important role in mRNA regulation, there is a major gap in our understanding of the sequence determinants critical for the binding o...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.9b00485
更新日期:2019-08-06 00:00:00
abstract::The use of cefoxitin, a poor substrate of the RTEM beta-lactamase, has allowed the kinetic and spectroscopic characterization of a covalent acyl-enzyme intermediate in the enzyme-catalyzed reaction. The rate of reappearance of catalytic activity in an enzyme sample diluted from an incubation with cefoxitin is nearly i...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00554a012
更新日期:1980-06-24 00:00:00