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

Extremely large separation factors (greater than 10(2)) were found for Na-Mg, K-Ca and Rb-Sr metal ion pairs on a cryptomelane-type hydrous manganese dioxide (CRYMO) ion exchanger. Ca2+ and Sr2+ ions were quantitatively separated from a thousand times of K+ and Rb+ ions on mole basis, respectively, by using the CRYMO column. The hopeful utilities of the CRYMO are suggested for the radiochemical ion-exchange separation of radiomagnesium and radiostrontium from K and Rb salt targets.
 ...
PMID:Separation of trace amounts of Ca2+ and Sr2+ from K+ and Rb+ with a hydrous manganese dioxide ion exchanger. 647 37

Staphylococcus aureus MF31 was grown to stationary phase in a complex medium at 30, 37, and 43 degrees C in the absence of salt and at 37 and 46 degrees C in the same medium supplemented with 1 M NaCl. The principal phospholipids were cardiolipin, phosphatidylglycerol, aminoacylphosphatidyl glycerol, mono- and di-glycosyldiglyceride, and traces of phosphoglycolipid. The proportion of cardiolipin decreased with increasing growth temperature, but only slightly in the presence of 1 M NaCl, while that of aminoacylphosphatidyl glycerol was unaffected by growth temperature in absence of salt, but was about halved in the presence of 1 M NaCl. The net negative charge per mole phospholipid was greatly increased in the presence of 1 M NaCl. In the absence of salt, temperature had no effect on the total lipid content, but cells from the 46 degrees C culture in 1 M NaCl contained 25% less total lipid. The proportion of phospholipid in the total lipids, both in the absence and presence of salt, declined with increasing growth temperature. The proportion of glycolipids, however, increased with temperature both in the absence and presence of salt. It is suggested that the increase in glycolipid content and in negative charge/mole phospholipid is a part of the adaptation of S. aureus to the combination of high temperature and 1 M NaCl giving its membrane increased stability and possibly helping to exclude Cl- anion from the cell interior.
 ...
PMID:Adaptational changes in Staphylococcus aureus MF 31 grown above its maximum growth temperature when protected by sodium chloride: lipid studies. 651 23

The authors explored the statics of Ca2+ and Sr2+ sorption from a saline, imitating the salt (mineral) composition of the blood plasma, and from blood plasma. As the plasma concentration was raised, there was a consistent decrease in ion sorption of KU = 2 X 8 cationite characteristic for M2+ complex formation in solution. Conventional constants for formation of complex compounds and mole proportions (%) of free (M2+) and complex forms (MLx-) metals were calculated. The time course of calcium and strontium sorption on KU = 2 X 8 ion-exchange resin from saline and blood plasma was studied. It was discovered that sorption from saline proceeded according to the externally diffusion kinetics type, whereas sorption from plasma according to the mixed type of the ion-exchange kinetics. The kinetic ratios were calculated for the indicated versions of sorption experiments. The mechanisms of sorption found in model experiments were extrapolated to dog experiments with blood decalcination, which supported the adequacy of experimental hemosorption under consideration.
 ...
PMID:[Ion-exchange sorption of calcium and strontium from blood and its plasma]. 662 28

We have examined the association of Ca2+ with phosphatidylserine/cholesterol and phosphatidylserine/dimyristoylphosphatidylcholine mixed monolayers using a surface radiocounting technique. No Ca2+ association with pure monolayers of the uncharged molecules was observed. The Ca2+/phosphatidylserine surface ratio was approximately 1:2 in expanded monolayers of the pure anionic lipid and in phosphatidylserine/phosphatidylcholine mixtures. An increase in surface-associated Ca2+ to a number ratio of 1:1 was observed in phosphatidylserine/cholesterol films when the mole fraction of cholesterol was raised to 0.5 and above and the phospholipid number density held constant. We interpret these findings as a prevention of intermolecular salt formation by the sterol. Further support is provided by particle electrophoresis.
 ...
PMID:Calcium association with phosphatidylserine. Modification by cholesterol and phosphatidylcholine in monolayers and bilayers. 669 75

In a study of human milk obtained in the first month of lactation, lipase and esterase activity were assayed. Bile salt-stimulated lipase (BSSL) and bile salt-stimulated esterase (BSSE) activities in colostrum were similar to corresponding enzyme activities in transitional milk and in mature milk. BSSL and BSSE were significantly (P less than 0.001) correlated to one another, which suggests that lipase and esterase activities in milk are due to the same enzyme. When milk was allowed to stand at room temperature, in a refrigerator, or subjected to freezing and thawing, wide fluctuations were observed in lipase and esterase activities, but there was no systematic tendency for enzyme activity to increase or decrease. Heating milk to various temperatures between 40-55 degrees C resulted in progressive loss of enzyme activity. The activation energy for the process which inactivates the enzyme was found by linear regression to the Arrhenius plot to be 2 X 10(5) J X mole-1. Our findings suggest that lipase and esterase activity in human milk which is donated to hospitals and stored frozen can make a valuable contribution to fat digestion in the newborn infant, but pasteurization destroys the enzyme.
 ...
PMID:Bile salt-stimulated lipase and esterase activity in human milk after collection, storage, and heating: nutritional implications. 671 97

Thermally induced structural transition in the d(TTTTATAATAAA) d(TTTATTATAAAA) heteroduplex is characterized by UV-spectroscopy and differential scanning calorimetry. At low salt (less than 0.1 M) the occurrence of a cooperative transition in the lower temperature range, followed by a broad transition connected with small increase in absorbance is observed. At high salt (greater than or equal to 0.2 M) a single, monophasic transition appears. Linear dependence of the latter on log of salt concentration (dTm:dlogM = 14.2 degrees C) and of 1/Tm on log of oligomer concentration [derived therefrom delta H (v.H.) = 77.1 kcal/mole (duplex)] allows relating it to the melting of the heteroduplex helix. The non-cooperative transition, independent of oligomer concentration and similar to that of the single chain, was attributed to melting of short hairpin helices upon heteroduplex dissociation. Calorimetric enthalpy: 75.6 kcal/mole (duplex) proved significantly lower than predicted from known calorimetric data for poly[d(AT)] and poly d(A) X poly d(T).
 ...
PMID:Deoxydodecanucleotide heteroduplex d(TTTTATAATAAA). d(TTTATTATAAAA) containing the promoter Pribnow sequence TATAAT. I. Double-helix stability by UV spectrophotometry and calorimetry. 671 50

A method for estimation of constants of carbocyanine probe diS-C3-(5) partition between water and membrane phases was developed based on the analysis of fluorometric titration curves. The partition constants (K) of this dye were calculated (the ratio of dye mole fraction in membrane and water phases) for sarcoplasmic reticulum (SR) vesicles in sucrose K = (1.15 +/- 0.04) X 10(7) and salt K = (6.12 +/- 0.07) X 10(6) media and for the asolectine liposomes in salt medium K = (3.4 +/- 0.2) X 10(7). The probe partition between water and lipid phases was calculated for different membrane concentrations. Critical aggregation concentrations of probe in lipid phase were estimated to be approximately 8 mol. probe per 1000 mol. lipid for asolectine liposomes and approximately 9 mol. per 1000 mol. lipid for SR vesicles (both in salt medium), approximately 6 mol. per 1000 mol. lipid for SR vesicles in sucrose medium. On the basis of own and literature data a mechanism of voltage-sensitive probe response related to probe aggregation in membranes was suggested.
 ...
PMID:[Mechanism of the fluorescent response of carbocyanine probe diS-C3-(5) to membrane potential change]. 683 Aug 94

Comprehensive binding studies using direct and indirect methods yield stoichiometry and affinities for the binding of Mg X ADP and uncomplexed ADP to the active site of myosin subfragment-1. Additionally, the binding parameters for Mg2+ in the ternary complex protein X Mg X ADP are presented for the first time. The indirect method makes use of reactivity changes of the critical thiol-1 and thiol-2 groups, which occur upon the binding of the ligand at the active site. The affinity constants derived by this method are corroborated by two independent direct methods, equilibrium dialysis and centrifugation transport. For Mg2+, ADP and Mg X ADP just one mole of ligand binds/mole subfragment-1. The affinity of Mg X ADP at low ionic strength is 2.1 X 10(6) M-1 and only five-times lower in the absence of Mg2+. In the ternary complex Mg2+ has a low affinity of 4.1 X 10(4) M-1. At high ionic strength the uncomplexed ADP binds with a 43-times-lower affinity than Mg X ADP, whose affinity is 6.9 X 10(5) M-1. In this case Mg2+ interacts in the ternary complex with the higher affinity of 3.2 X 10(5) M-1, implying that at high salt concentration it plays a more prominent role in anchoring ADP at the active site.
 ...
PMID:Interaction of ADP and magnesium with the active site of myosin subfragment-1 observed by reactivity changes of the critical thiols and by direct binding methods at low and high ionic strength. 683 46

Phosphatidylserine decarboxylase from Escherichia coli, an intrinsic membrane protein, catalyzes the conversion of phosphatidylserine to phosphatidylethanolamine. The physical and kinetic properties of the purified enzyme were studied in several detergents under assay conditions. The active form of the enzyme is an oligomer, probably a trimer, and the enzyme activity was unaffected by the concentration of the nonionic poly(oxyethylene) ether detergent present in the assay medium, so long as the detergent micelle/substrate mole ratio was less than one. When this ratio was greater than one, the detergent acted as an inhibitor by competing with enzyme-containing micelles for substrate. The zwitterionic and bile salt detergents that were tested inactivated the enzyme by dissociating the oligomer. The native, Triton X-100 solubilized, enzyme was modified with a cross-linking reagent. Activity of the cross-linked enzyme was retained after the Triton X-100 was replaced by a zwitterionic sulfobetaine detergent and conformed to the same kinetic model as with the poly(oxyethylene) ether detergents. The cross-linked enzyme was also active when solubilized by the bile salt detergents although the activity did not conform to any simple kinetic model. These data indicate that the oligomer is the active form of the enzyme under assay conditions and that certain nondenaturing detergents can inactivate this enzyme by dissociating the enzyme complex.
 ...
PMID:Kinetics and protein subunit interactions of Escherichia coli phosphatidylserine decarboxylase in detergent solution. 701 77

Rotational diffusion of band 3 proteins in human erythrocyte membranes is measured by observing flash-induced transient dichroism of the triplet probe, eosin-maleimide. At physiological temperature, both fast and slowly rotating populations of band 3 are present in the membrane. Rotational motion of band 3 is the same in membranes from young and old erythrocytes and is unchanged when the cholesterol:phospholipid mole ratio is varied from 1.34 to 1.66. Antibodies against glycophorin A immobilize band 3, indicating an association between these two integral membrane proteins. However, glycophorin A has little effect on the rotational motion of the complex, since band 3 rotation in En(a-) membranes (which lack glycophorin A) is similar to that observed in normal membranes. Cleavage of the cytoplasmic segment of band 3 by trypsin produces a considerable enhancement of band 3 rotational mobility. A similar effect is seen following extraction of bands 2.1 and 4.1 by sequential low salt-high salt treatment. It is concluded that up to 40% of band 3 has restricted rotational mobility due to interaction with the erythrocyte cytoskeleton.
 ...
PMID:Rotational diffusion of erythrocyte membrane proteins. 702 77


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>