BINDING STUDIES

10/5/98


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NOTICE: This material is copyrighted and all right are reserved. (c) 1998 J. E. Wampler
Students may make a single copy for study purposes.

Table of Contents

{1} BINDING STUDIES

{2} Big problems and issues...

{3} Binding Experiments covered by these lectures:

{4} Irreversible binding or Titration with a "pulled” reaction

{5} Why is the end-point not sharp?

{6} Why...

{7} In addition, [L] often is detected in measuring [EL]

{8} One binding site, one:one interaction:

{9} Also...

{10} Typical one-to-one binding experiments

{11} Two types of experiments...

{12} No experimental constraints…

{13} However, the + sign doesn’t make sense, i.e. x increases indefinitely!

{14} Prior to computers and fancy calculators,

{15} What if x is only on a relative scale?

{16} Terms become dimensionless

{17} WARNING...

{18} With experimental constraint that Lo>>Eo

{19} This equation:

{20} These equations allow graphical determination of Kd:

{21} This model, Y = Lo/(Kd + Lo)

{22} Multiple Equivalent, Independent Sites

{23} Solution in terms of things we know (Eo and Lo):

{24} Langmuir like derivation,

{25} With Y = [AL]/nEo measured as Signal/Signalmax

{26} Y and R are fundamentally different.

{27} Remember:

{28} Like the Langmuir isotherm, this equation linearizes several ways:

{29} Other Multi-site Models and Cooperativity

{30} Consider two such sites:

{31} General Form of 2-site Equation:

{32} General forms of other multisite models:

{33} All of these equations (1-site, 2-site, 3-site and 4-site) generate a family of OVERLAPPING curves.

{34} Positive and Negative Cooperativity

{35} Negative Cooperativity

{36} Measures of Cooperativity:

{37} 2) The Hill Plot Slope, h

{38} Hill coefficient...

{39} 3) Scatchard Plot (BOO-HISS) Maximum, Ymax

Author: John E. Wampler

Email: wampler@bchiris.bmb.uga.edu

Home Page: http://bmbiris.bmb.uga.edu/wampler/8010