(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.
Off
Definition:
(adv.) In a general sense, denoting from or away from; as:
(adv.) Denoting distance or separation; as, the house is a mile off.
(adv.) Denoting the action of removing or separating; separation; as, to take off the hat or cloak; to cut off, to pare off, to clip off, to peel off, to tear off, to march off, to fly off, and the like.
(adv.) Denoting a leaving, abandonment, departure, abatement, interruption, or remission; as, the fever goes off; the pain goes off; the game is off; all bets are off.
(adv.) Denoting a different direction; not on or towards: away; as, to look off.
(adv.) Denoting opposition or negation.
(interj.) Away; begone; -- a command to depart.
(prep.) Not on; away from; as, to be off one's legs or off the bed; two miles off the shore.
(a.) On the farther side; most distant; on the side of an animal or a team farthest from the driver when he is on foot; in the United States, the right side; as, the off horse or ox in a team, in distinction from the nigh or near horse or ox; the off leg.
(a.) Designating a time when one is not strictly attentive to business or affairs, or is absent from his post, and, hence, a time when affairs are not urgent; as, he took an off day for fishing: an off year in politics.
(n.) The side of the field that is on the right of the wicket keeper.