In huangrh/radii: Determine Hydrodynamic Radius from Gel Filtration

Gel filtration columns columns:

• Superdex 200 (16/60; GE Healthcare)
• Superose 6 (10/300; GE Healthcare)

Standard proteins of known Rh:

• bovine thyroglobulin (8.5 nm, 670 kDa)

• bovine IgG (5.22 nm, 158 kDa)

• chicken ovalbumin (2.75 nm, 44 kDa)
• horse myoglobin (1.89 nm, 17 kDa)

Partition coefficient (s):

The partition coefficient (s) was calculated for each standard protein from the observed elution volume (Vs), total column volume (Vt), and void volume (Vo):

$$ s = \frac{(Vs - Vo)}{(Vt - Vo)} $$

Linear regression analysis of stokes radius:

Linear regression analysis of the values for Rh as a function of the inverse error function complement $(erfc^{-1})$ of sigma (s) gave excellent correlation coefficients (R2 > 0.98), and the fitted parameters did not vary significantly for several chromatography buffer conditions:

• 20 mM Hepes (pH 7.4), 150 mM NaCl, 5 mM EDTA (orange circles);
• 20 mM Hepes (pH 7.4), 10 mM CaCl2 (blue circles);
• 20 mM Mes (pH 6.2), 10 mM CaCl2 (green circles).

Partition coefficients for other proteins were used to calculate Rh according to the indicated equations.

## see RH110806A for more detail
library("knitr"); library(radii)
# kable(radii::protein_std, format = "markdown")

## Superdex 200 10-300GL 
vt = 21.54
vo = 8.21
protein_std$sigma <- radii::partition_coef(protein_std$ve, vt = vt, vo=vo)
protein_std$erfcinv <- radii::erfcinv(protein_std$sigma)
# 
kable(protein_std, format = "markdown")
protein_std <- na.omit(protein_std)
with(protein_std, plot(erfcinv, radii))
fit <- lm (radii~erfcinv-1, data = protein_std)
summary(fit)
xdat <- seq(min(protein_std$erfcinv), max(protein_std$erfcinv),by = 0.01 )
pred <- predict(fit, newdata = data.frame(erfcinv=xdat))
lines(xdat,pred)

References:

Hydrodynamic radius, Rh, can refer to the Stokes radius of a polymer or other macromolecule.
1. Hydrodynamic radius
2. Stokes radius
3. Ackers GK (1967) J Biol Chem 242: 3237-3238

huangrh/radii documentation built on May 17, 2019, 9:10 p.m.