Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The regulation patterns of gastric acid secretion in rats were investigated. Pentagastrin and histamine stimulate gastric acid secretion, but the inhibitors of DNA-dependent synthesis of RNA and of proteins prevent only the pentagastrin action. It has been found that pentagastrin induces histidine decarboxylase in gastric mucosa, ensuring local accumulation of histamine. The latter activates adenylate cyclase and results in 3',5'-AMP accumulation in gastric tissues. The administration of pentagastrin, histamine or 3',5'-AMP enhances the activity of gastric carbonic anhydrase, the enzyme which takes part in HCl formation. The data suggest that these three compounds act sequentially (pentagastrin leads to histamine leads to3',5'-AMP) and the effect of the last one could be mediated through 3',5'-AMP dependent protein kinase. The experiments in vitro demonstrated that gastric carbonic anhydrase can be separated into two isoenzymes and thephosphorylation of one of them by the 3',5'-AMP dependent protein kinase sharply increases its activity. The findings raise the possibility that histamine and 3',5'-AMP, mediating gastrin action, form together with enzymes (histidine decarboxylase, adenylate cyclase, protein kinase, carbonic anhydrase) a caascade of amplifiers. Autoradiographic studies have shown that [3H]-pentagastrin is not bound by oxyntic cells but adheres preferentially to histamine-producing alpha-like endocrine cells and to the chief cells, while 3H-histamine adheres preferentially to oxyntic and to chief cells. Electron microscopy indicates that only pentagastrin (but not histamine) initiates in alpha-like endocrine cells ultrastructural changes characteristic for induction. Pentagastrin, histamine and 3',5'-AMP administration produces in oxyntic cells ultrastructural changes typical for the secretion processes. These results lead to assumption that pentagastrin (gastrin) induces histidine decarboxylase in alpha-like endocrine cells of gastric glands. Histamine which is secreted enhances adenylate cyclase activity in the neighbouring oxyntic cells where 3',5'-AMP dependent protein kinase activates carbonic anhydrase by means of phosphorylation. These different cells form, probably, a multicellular functional unit for gastric acid secretion.
Mol Cell Biochem 1976 Sep 30
PMID:Integration of biochemical functions of different cells of rat gastric mucosa for hydrochloric acid secretion. 18 10

Proteins from grossly and histologically normal human aortic intimas and human aortic intima with fatty streaks or fibro-fatty lesions were extracted with 9 M urea mixture. Protein extracts were mixed with an internal absorbance calibrator (carbonic anhydrase) and subsequently separated by two-dimensional gel electrophoresis, silver stained, and quantitated by a laser beam densitometer. The vascular-origin proteins actin, tropomyosin-like proteins, tubulin, glycoprotein G35, and two myosin light chains were present in the highest amounts in normal aortic intima (27-year-old male). Quantitation of vascular-origin proteins in aortic intima with a fibro-fatty lesion from the same subject showed a slight decrease in relative amount of these proteins as compared to the normal intima. Several polypeptides (P15, P18, P60, P110b) and plasma-derived proteins not observed in the normal intima were found in fibro-fatty lesion (albumin, haptoglobin beta-chain, fibrinogen beta-chain, alpha 1-HS-glycoprotein). Other proteins which were present in very low amounts in the normal intima (transferrin, alpha 1-antitrypsin, apolipoprotein A-1, P56, P190) were found to be major proteins of intima with fibro-fatty lesion. Differences in relative amount of plasma-derived and vascular-origin proteins between normal intima and intima with fatty streaks, studied in a large number of specimens from 38 thoracic intimas and 18 paired abdominal intimas (16-34 years old) were less prominent. Statistically significant increases of the albumin/actin ratio were found in fatty streaks as compared to paired normal intimas as well as in the mean value of albumin/actin ratio in the group of fibro-fatty lesions (mean = 6.1) as compared to the group of fatty streaks (mean = 1.7) or normal intima (mean = 0.7). Several lesion unique proteins were observed; however, the frequency of the occurrence of these proteins in 41 specimens with lesion was low. No significant differences were observed in intima protein pattern and quantities of selected intima proteins between paired thoracic and abdominal aortas.
Exp Mol Pathol 1992 Dec
PMID:Quantitative alteration of some aortic intima proteins in fatty streaks and fibro-fatty lesions. 128 71

The interaction of formate and acetate ions with cobalt-substituted carbonic anhydrase (CA) has been investigated through 13C-NMR and one-dimensional and two-dimensional 1H-NMR spectroscopy. 13C data on formate are consistent with a regularly coordinated ligand, as previously proposed for the acetate anion [Bertini, I., Luchinat, C. & Scozzafava, A. (1977) J. Chem. Soc. Dalton Trans., 1962-1965]. 1H-NOE experiments on both anions give evidence of through-space interactions between ligand protons and protein protons. The latter are assigned to specific residues in the active cavity through nuclear Overhauser effect spectroscopy (NOESY) experiments. The 13C-derived and 1H-derived constrains allow reliable docking of these ligands in the active-site cavity. The resulting geometries are similar to one another and consistent with five-coordinated structures around the metal ion, as previously proposed from electronic spectroscopy [Bertini, I., Canti, G., Luchinat, C. & Scozzafava, A. (1978) J. Am. Chem. Soc. 100, 4873-4877]. The results are discussed in light of the current debate on anion binding to metal ions in carbonic anhydrase [Lindahl, M., Svensson, A. & Liljas, A. (1992) Proteins, in the press]; Bertini, I., Luchinat, C., Pierattelli, R. & Vila, A. J. (1992) Inorg. Chem., in the press; Banci, L. & Merz, K. (1992) unpublished results] and, in particular, of the proposed long Zn-O distance found in the recent X-ray results on the formate adduct [Hakanson, K., Carlsson, M., Svensson, A. & Liljas, A. (1992) J. Mol. Biol., in the press].
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PMID:The interaction of acetate and formate with cobalt carbonic anhydrase. An NMR study. 139 67

In order to obtain a better structural framework for understanding the catalytic mechanism of carbonic anhydrase, a number of inhibitor complexes of the enzyme were investigated crystallographically. The three-dimensional structure of free human carbonic anhydrase II was refined at pH 7.8 (1.54 A resolution) and at pH 6.0 (1.67 A resolution). The structure around the zinc ion was identical at both pH values. The structure of the zinc-free enzyme was virtually identical with that of the native enzyme, apart from a water molecule that had moved 0.9 A to fill the space that would be occupied by the zinc ion. The complexes with the anionic inhibitors bisulfite and formate were also studied at neutral pH. Bisulfite binds with one of its oxygen atoms, presumably protonized, to the zinc ion and replaces the zinc water. Formate, lacking a hydroxyl group, is bound with its oxygen atoms not far away from the position of the non-protonized oxygen atoms of the bisulfite complex, i.e. at hydrogen bond distance from Thr199 N and at a position between the zinc ion and the hydrophobic part of the active site. The result of these and other studies have implications for our view of the catalytic function of the enzyme, since virtually all inhibitors share some features with substrate, product or expected transition states. A reaction scheme where electrophilic activation of carbon dioxide plays an important role in the hydration reaction is presented. In the reverse direction, the protonized oxygen of the bicarbonate is forced upon the zinc ion, thereby facilitating cleavage of the carbon-oxygen bond. This is achieved by the combined action of the anionic binding site, which binds carboxyl groups, the side-chain of threonine 199, which discriminates between hydrogen bond donors and acceptors, and hydrophobic interaction between substrate and the active site cavity. The required proton transfer between the zinc water and His64 can take place through water molecules 292 and 318.
J Mol Biol 1992 Oct 20
PMID:Structure of native and apo carbonic anhydrase II and structure of some of its anion-ligand complexes. 143 93

A full-length cDNA clone encoding carbonic anhydrase was isolated from an Arabidopsis thaliana (Columbia) leaf library. Comparison of the derived amino acid sequence obtained from this clone with those of pea and spinach reveals a considerable degree of identity. The carbonic anhydrase cDNA was used to probe the level of RNA encoding this protein in the leaves of plants grown in elevated CO2 (660 ppm). We have found that under these conditions the steady-state level of carbonic anhydrase mRNA was increased in comparison with control plants grown in normal atmospheric concentrations of CO2 (330 ppm). This raises the intriguing possibility that there exists in higher plants a mechanism for perceiving and responding to changes in environmental CO2 concentrations at the genetic level.
Plant Mol Biol 1992 Dec
PMID:Arabidopsis thaliana carbonic anhydrase: cDNA sequence and effect of CO2 on mRNA levels. 146 47

The three-dimensional structure of a complex between catalytically active cobalt(II) substituted human carbonic anhydrase II and its substrate bicarbonate was determined by X-ray crystallography (1.9 A). One water molecule and two bicarbonate oxygen atoms are found at distances between 2.3 and 2.5 A from the cobalt ion in addition to the three histidyl ligands contributed by the peptide chain. The tetrahedral geometry around the metal ion in the native enzyme with a single water molecule 2.0 A from the metal is therefore lost. The geometry is difficult to classify but might best be described as distorted octahedral. The structure is suggested to represent a water-bicarbonate exchange state relevant also for native carbonic anhydrase, where the two unprotonized oxygen atoms of the substrate are bound in a carboxylate binding site and the hydroxyl group is free to move closer to the metal thereby replacing the metal-bound water molecule. A reaction mechanism based on crystallographically determined enzyme-ligand complexes is represented.
J Mol Biol 1992 Dec 20
PMID:Structure of cobalt carbonic anhydrase complexed with bicarbonate. 147 87

Kinetic values for 14 sulfonamides and carbonic anhydrase (equivalent of isozyme II) were determined directly by measurement of association rate constants (kon) and equilibrium constants (KI), yielding dissociation rate constants, koff. Values for kon (in liter/mol sec-1) ranged from 0.003 to 31 x 10(6), whereas KI ranged from 0.7 to 17,000 x 10(-9) M. The koff range was very small, 0.01-0.05 sec-1. Thus, the activity, which is usually thought of as reflecting KI, is entirely a function of the association rate. This is not the common situation in enzyme-inhibitor reactions. The koff range is faster by several orders of magnitude than drug decay from plasma, so equilibrium is always achieved at the enzyme site in vivo, after parenteral administration of acetazolamide, methazolamide, or ethoxzolamide. For topical administration, as for MK-927 to reduce intraocular flow and pressure, the quantitative relation between free drug in tissue and that bound to enzyme in ciliary process is not so clear. Thus, koff might be an independent factor in pharmacological activity. The reaction of anions with carbonic anhydrase is entirely different, in that variations in KI are chiefly determined by koff.
Mol Pharmacol 1992 Feb
PMID:Direct measurements of the rate constants of sulfonamides with carbonic anhydrase. 153 18

Effects of the s.c. administration of various doses of estradiol propionate (E.P.; 25-500 micrograms/kg) on the activities of carbonic anhydrase (CA), Mg(2+)-dependent ATPase and Mg(2+)-dependent, HCO3(-)-stimulated ATPase (Mg(2+)-HCO3(-)-ATPase) in rat duodenal mucosa and kidney cortex, and on body weight, organ weight and serum concentrations of testosterone and estradiol-17 beta, were examined in adult male, female, testectomized and ovariectomized rats. In normal male rats, activities of cytosol CA and brush border Mg(2+)-HCO3(-)-ATPase in the kidney were increased in a dose-dependent manner and reached 1.6- and 2-fold of controls, respectively, after consecutive administration (daily for 7 days) of 500 micrograms E.P. with no changes in either enzyme activities in duodenal mucosa. The positive correlations (P less than 0.01) were observed by linear regression analysis between serum concentration of estradiol-17 beta and kidney cytosol CA or kidney brush border Mg(2+)-HCO3(-)-ATPase activities. In normal female rats, activities of cytosol CA and brush border Mg(2+)-HCO3(-)-ATPase in the duodenal mucosa, and brush border Mg(2+)-HCO3(-)-ATPase activity in the kidney were increased by E.P. administration (100 and 500 micrograms/kg, daily for 7 days), however, kidney cytosol CA activity did not change by any dosage. Behavior of a part of both enzymes to E.P. in testectomized rats was altered almost in the same way to that observed in normal female rats and vice versa in ovariectomized rats. Body weight was decreased, in general, by consecutive administration of E.P. in a dose-dependent manner, and kidney weight was increased by E.P. in both male and female rats.
J Steroid Biochem Mol Biol 1991 Sep
PMID:Sexual difference and organ specificity of the effect of estradiol on carbonic anhydrase and Mg(2+)-HCO3(-)-ATPase activities isolated from duodenal mucosa and kidney cortex of male and female rats: preliminary study with crude enzyme samples. 183 40

To achieve a better understanding of the biochemical basis of obesity, we have undertaken comparative analyses of adipose tissue of lean and obese mice. By two-dimensional gel analysis, carbonic anhydrase-III (CA III) has been identified as a major constituent of murine adipose tissue. Quantitative comparisons of CA III protein and mRNA levels indicate that this enzyme is expressed at lower levels in adipose tissue from animals that were either genetically obese or had experimentally induced obesity compared to levels in the corresponding lean controls. This decrease in CA III expression was unique to adipose tissue, since other CA III-containing organs and tissues did not show a change when lean and obese animals were compared. Additionally, levels of CA III in adipose tissue from obese animals responded to acute changes in energy balance of the animal. These results are discussed in light of possible metabolic roles for CA III.
Mol Endocrinol 1991 Jun
PMID:Expression of CA III in rodent models of obesity. 192

A computer-based pattern recognition (PR) approach has been applied to the classification and interrogation of 1H NMR-generated urinalysis data, in a variety of experimental toxicity states in the rat. 1H NMR signal intensities for each endogenous urinary metabolite were regarded as coordinates in multidimensional space and analyzed using PR methods, through which the dimensionality was reduced for display and categorization purposes. The changes in the NMR spectral patterns were characterized by 17 metabolic dimensions, which were then analyzed by employing the unsupervised learning methods of hierarchical cluster analysis, two-dimensional nonlinear map (NLM) analysis, and two- or three-dimensional principal components analysis (PCA). Different types of toxin (hepatotoxins and cortical and papillary nephrotoxins) were classified according to NMR-detectable biochemical effects. PCA provided consistently better results than NLMs in terms of discrimination of toxicity type, and maps based on correlation matrices also gave improved discrimination over those based on raw data. Various refinements in the data analysis were investigated, including taking NMR urinalysis data at three time points after exposure of the rats to six different nephrotoxins, as well as employing a dual-scoring system (time and magnitude of change). The maps generated from the time-course information produced the best discrimination between nephrotoxins from different classes. The robustness of the classification methods (in particular NLMs and PCA based on correlation matrices) and the influence of the addition of new scored biochemical data, reflecting dose-response situations, nutritional effects on toxicity, sex differences in biochemical response to toxins, the addition of a new toxin class (cadmium chloride, a testicular toxin and renal carbonic anhydrase inhibitor), and an additional metabolite descriptor (creatine), to the PR analysis were also evaluated. Initial training set maps were fundamentally stable to the addition of new data, and both NLM and PCA methods correctly "predicted" the toxicological effects from NMR data for test compounds, suggesting that the approach using PR and 1H NMR urinalysis for the generation and classification of acute toxicological data has wide applicability.
Mol Pharmacol 1991 May
PMID:Application of pattern recognition methods to the analysis and classification of toxicological data derived from proton nuclear magnetic resonance spectroscopy of urine. 203 35


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