(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.
Toff
Definition:
Example Sentences:
(1) Tory toffs repelling undesirable immigrants, providing better schools, using welfare reform as a pathway to work, clearing vandals, yobs and drunks from the streets and standing up to our masters in Brussels would be very popular, and the word would soon be forgotten.
(2) It’s that the British are so fascinated by toffs that we give them a free pass as long as they stay on brand.
(3) It has got to stop, this fashion for toffs to pose as ordinary.
(4) It has let itself be called a government of unfeeling toffs … The abiding sin of the government is not that some ministers are rich, but that it seems unable to manage its affairs competently."
(5) There is still a sizeable chunk of the world which sees the English as top-hatted toffs who can be cruel to their urchins, so it remains to be seen what they will think after the British Council's celebrations of Charles Dickens' bicentenary.
(6) "You, and George, in particular, have been portrayed as public school toffs.
(7) I will leave the public to judge his actions.” Mick Cash, general secretary of the Rail, Maritime and Transport (RMT) union, said it should be no surprise that his black cab members across London were considering “a boycott of the Tory toff David Mellor over his outrageous, pompous and disgraceful tirade against one of their colleagues”.
(8) Rex Hunt, fully dressed in his governor's tights and ostrich plumes, was widely seen, not least by toffs in the Foreign Office (FCO), as a slightly Wodehousian figure, the kind more likely to be seen in slacks propping up the golf club bar in a colonial outpost.
(9) A decade earlier, the clever grocer's daughter Margaret Thatcher had devastated Tory toffs with a gale-force combination of vicious class resentment and sexy ankles.
(10) Champagne socialism in action The Mirror's determination to photograph Tory toffs clutching glasses of champagne did not end with the page one Cameron shot which led to the Tory leader renouncing the stuff ("He's had a good talking to," said Samantha C) for the duration of the class war.
(11) Hutchings, a mother-of-four, also declared that she was not a "rich Tory toff" and said she once had to borrow £1.80 to pay for parking from members of a job club she ran because the cash machine would not give her any money.
(12) It affects how voters see Tory choices on tax, welfare and public services – toffs and plebs – in the most damaging way possible.
(13) Fourteen-year-olds pontificating on this must be making the old field marshal turn in his grave, and this debate also perpetuates the myth that British soldiers were "lions led by donkeys", the idea that the brave ordinary Tommy was let down by the brandy-soaked toffs in charge.
(14) As the tagline – "May the best man live" – suggests, it's basically the same old flick with the same old schtick: the Stath tops baddies, boffs toffs (he's a one-man manifesto for geezer supremacy), and cops off with a blondie.
(15) This government has difficulty in managing a non-story about the chancellor upgrading his ticket on a train, or the stupidity of the former chief whip (who is no toff) behaving like a saloon-bar bore.
(16) The first thing you learn about him is what a toff he was: born into a banking family, Fleming's father was Conservative MP and friend of Churchill, Valentine Fleming.
(17) Jonathan was in constant demand whenever a comic toff or a bumbling cleric was called for on TV.
(18) Before Sky, Schuster was head of development at Toff Media, the specialist drama and comedy company founded by Alexander Armstrong and Ben Miller.
(19) Miliband rejected criticisms of Labour's election broadcast, which portrayed the Liberal Democrat leader, Nick Clegg, as the "Un-credible Shrinking Man" and Conservative cabinet ministers as out-of-touch "toffs".
(20) Your report on Vladimir Putin’s progress from pariah to powerbroker ( Putin has been taken off the menu and returned to the top table , 18 November) reminds me of previous instances where reactionary toffs let their prejudices over Russia cloud their judgment.