بخشی از پاورپوینت
--- پاورپوینت شامل تصاویر میباشد ----
اسلاید 1 :
Simple, straightforward technique for assaying
1.Solution conformation of biomolecules & water binding
2.Molecular weight of biomolecules
3.Flexibility
اسلاید 2 :
1.“U-tube” (Ostwald or Ubbelohde)
2.“Cone & Plate” (Couette)
اسلاید 3 :
Types of Viscometer:
1.“U-tube” (Ostwald or Ubbelohde)
2.“Cone & Plate” (Couette)
اسلاید 4 :
Types of Viscometer:
1.“U-tube” (Ostwald or Ubbelohde)
2.“Cone & Plate” (Couette)
اسلاید 5 :
We define the relative viscosity hr as the ratio of the viscosity of the solution containing the macromolecule, h, to that of the pure solvent in the absence of macromolecule, ho:
hr = h/ho units?
For a U-tube viscometer, hr = (t/to). (r/ro)
اسلاید 6 :
Reduced viscosity
The relative viscosity depends (at a given temp.) on the concentration of macromolecule, the shape of the macromolecule & the volume it occupies.
If we are going to use viscosity to infer on the shape and volume of the macromolecule we need to eliminate the concentration contribution.
The first step is to define the reduced viscosity
hred = (hr– 1)/c
If c is in g/ml, units of hred are?
اسلاید 7 :
The Intrinsic Viscosity [h]
The next step is to eliminate non-ideality effects deriving from exclusion volume, backflow and charge effects. By analogy with osmotic pressure, we measure hred at a series of concentrations and extrapolate to zero concentration:
اسلاید 8 :
A variant of the Huggins equation is:
hred = [h] (1 + kh.c) kh: ml/g
and another important relation is the SOLOMON-CIUTA relation, essentially a combination of the Huggins and Kraemer lines:
[h] ~ (1/c) . [2 (hr – 1) – 2 ln(hr) ] 1/2
The Solomon-Ciuta equation permits the approximate evaluation of [h] without a concentration extrapolation.
اسلاید 9 :
Intrinsic Viscosity and its relation to macromolecular properties
[h] so found depends on the shape, flexibility and degree of (time-averaged) water-binding, and for non-spherical particles the molecular weight:
اسلاید 10 :
Intrinsic Viscosity and Protein Shape and Hydration
[h] = n . vs (1)
n: Simha-Saito function (function of shape & flexibility) vs: swollen specific volume, ml/g (function of H2O binding)
n: Einstein value of 2.5 for rigid spheres >2.5 for other shapes
vs: volume of “hydrated” or “swollen” macromolecule per . unit anhydrous mass
= v + (d/ro) = v . Sw
d: “hydration” (g H2O/g protein)
v: partial specific volume (anhydrous volume per unit . anhydrous mass)
