(1) The time course of the binding of a radioligand in the presence of a competing unlabeled ligand was analyzed in terms of rate constants of association (kon) and dissociation (koff) for binding of the radioligand and the competitor.
(2) Evidence is presented that the dependence of pH on koff for hDHFR accounts for the shape of the kcat versus pH curve for both hDHFR as well as its F31L variant and contributes to the higher efficiency of hDHFR compared with bacterial DHFR.
(3) In intact cells, the koff value for [3H]DTLET was lower than that found in membrane fractions in Krebs-HEPES and similar to that observed in membrane preparations in Tris-HCl supplemented with 30 mM NaCl.
(4) These results enable calculation of real time rate values for the enzyme-primer association (kon = 5.7 x 10(8) M-1 s-1) and dissociation (koff = 1.6 s-1).
(5) Dissociation kinetic studies indicated that the receptor types A, B, and C had different koff values allowing, therefore, a separate study of their binding properties.
(6) 3H-(-)-bupranolol associated to beta-adrenoceptors of lung membranes with a kon 1.21 X nmol-1 X min-1 and dissociated with a koff of 0.26 min-1.
(7) A temperature-dependence study of koff for the cortisol and progesterone complexes gave values of 0.0028 s-1 and 0.012 s-1 at 4 degrees C, respectively, and 0.88 s-1 and 4.5 s-1 at 37 degrees C, with progesterone dissociating about four to five times faster over the entire temperature range.
(8) One of three bound nucleotide molecules is localized at the site with Kd approximately 10(-7) M and released with koff approximately 0.1 s-1.
(9) The dissociation constant of the enzyme-inhibitor complex (koff) shows no pH dependence between pH 4 and pH 9.5.
(10) 2-(Trimethylammonio)ethyl pyrophosphate also inhibits with Ki' = 7 X 10(-7) M, kon' = 4.4 X 10(4) M-1 min-1, and koff = 0.03 min-1.
(11) The results of the inhibition of HL elastase by 175 benzoxazinones are reported herein with reference to hydrophobicity constants D, alkaline hydrolysis rates kOH-, inhibition constants Ki, and their component acylation and deacylation rate constants, kon and koff, respectively.
(12) In locust, 500 mM ethanol did not affect either Kon or Koff.
(13) The dissociation equilibrium constant of the binding was found to be 4 x 10(-9) M at 37 degrees C. Kinetic studies of complex formation and dissociation revealed that the kon and koff were 4 x 10(6) M-1 s-1 and 6.8 x 10(-2) s-1 respectively at 16 degrees C. Equilibrium competition experiments showed that the enzyme has varying affinities for a variety of nucleic acids in the order 23S rRNA greater than 16S rRNA greater than M13 DNA, f2 RNA greater than tRNA.
(14) These compounds are "slow-binding" inhibitors of HLE and, thus, allow the determination of Ki, the dissociation constant for the stable complex of inhibitor and enzyme, as well as kon and koff, the rate constants for formation and decomposition of this complex.
(15) We have treated hypospadia that is strictly glandular either with Duckett's Magpi procedure (54 cases, 49 long-term follow-up, 47 good results, retraction of the meatus in two), or Koff's advancement procedure if there is a grow in glans (13 cases, 12 good results, on requiring meatostomy).
(16) External pH effect was primarily mediated by modulation of kon; koff was again relatively unaffected.
(17) We measured the apparent individual on and off rate constants (kon and koff) for bFGF binding to these two sites on intact cells and to each class of binding site in the absence of the other.
(18) In the acidic form, koff was increased 5- and 20-fold when Arg 48 was replaced with Lys and Leu, respectively, while in the acidic form of mutants that possess Arg 48, koff was similar to that observed in CCP(MI).
(19) Butanol binds at the effector site but does not effect koff of TPB.
(20) For Cd(II) or Mg(II) at the B site in place of Zn(II), koff less than or equal to 1 s-1 X Cl-ion, which appears to coordinate the A site metal ion, enhances koff, suggesting that both Cl- and HPO2-4 can coordinate the A site metal ion in a 5-coordinate intermediate.
Mast
Definition:
(n.) The fruit of the oak and beech, or other forest trees; nuts; acorns.
(n.) A pole, or long, strong, round piece of timber, or spar, set upright in a boat or vessel, to sustain the sails, yards, rigging, etc. A mast may also consist of several pieces of timber united by iron bands, or of a hollow pillar of iron or steel.
(n.) The vertical post of a derrick or crane.
(v. t.) To furnish with a mast or masts; to put the masts of in position; as, to mast a ship.
Example Sentences:
(1) of PLA2 caused marked degranulation of mast cells in the rat mesentery which was facilitated by addition of calcium ion (10 mM) but antagonized by pretreating with three antiinflammatory agents.
(2) In later phases, mast cells appeared in the newly formed marrow in the external callus.
(3) Our prospective study has defined a number of important variables in patients with clinical evidence of mast cell proliferation that can predict both the presence of SMCD and the likelihood of fatal disease.
(4) In the dark cortical zone of the nodes (III group) there occur tissue basophils (mast cells), that, together with increasing number of acidophilic granulocytes and appearance of neutrophilic cells, demonstrates that there is an inflammatory reaction in the organ studied as a response to the lymphocytic suspension injected.
(5) Type I and Type II mast-cell degranulation was noted but was not universal.
(6) They clearly demonstrate the phenomenon of mast cells degranulation.
(7) The early absolute but transient dependence of these A-MuLV mast cell transformants on a fibroblast feeder suggests a multistep process in their evolution, in which the acquisition of autonomy from factors of mesenchymal cell origin may play an important role.
(8) The findings suggest that mast cell prostaglandins are an important factor in the pathogenesis of pruritus and that local vascular responses may trigger mast cell degranulation.
(9) 18 patients with typical sporadic Amyotrophic Lateral Sclerosis (ALS) were investigated by the Motor Accuracy and Speed Test (MAST) and 18 healthy age- and-sex-matched volunteers, acted as controls.
(10) When PMC purified to greater than 99% purity were cultured in methylcellulose with IL-3 and IL-4, approximately 25% of the PMC formed colonies, all of which contained both berberine sulfate-positive and berberine sulfate-negative mast cells.
(11) But we sent out reconnoitres in the morning; we send out a team in advance and they get halfway down the road, maybe a quarter of the way down the road, sometimes three-quarters of the way down the road – we tried this three days in a row – and then the shelling starts and while I can’t point the finger at who starts the shelling, we get the absolute assurances from the Ukraine government that it’s not them.” Flags on all Australian government buildings will be flown at half-mast on Thursday, and an interdenominational memorial service will be held at St Patrick’s cathedral in Melbourne from 10.30am.
(12) Mice homozygous for mutations at either locus exhibit several phenotypic abnormalities including a virtual absence of mast cells.
(13) This initial observation of release of eosinophil chemotactic factor of anaphylaxis in vivo along with histamine assigns the mast cell a central role in cold urticaria.
(14) Their presence was established both by staining for mast cells at light microscopic level and by electron microscopy.
(15) Pretreatment of rat peritoneal mast cells with either Staurosporine or an analog K-252a, lead to a dose-related inhibition of histamine release when stimulated with Anti-IgE (IC50: Staurosporine = 110 nM; K-252a = 100 nM).
(16) The ammoniacal silver method, which identifies basic proteins, gives a positive reaction in cytoplasmic granules of rat peritoneal mast cells.
(17) Cytokine secretion by activated lymphocytes or mast cells is preceded by dramatic stabilization of the normally labile GM-CSF mRNA.
(18) Forty-seven patients were brought to the Emergency Department with a good blood pressure which probably would not have existed without the use of MAST Trousers.
(19) Furthermore, using rat mast cells, the binding assay in conjunction with histamine releasing assay may be utilized to predict the in vivo histamine releasing potential of new LHRH peptides which are of clinical importance.
(20) Six dogs had increased numbers of mast cells in peripheral blood or buffy coat smears.