Symbol

Description

Units

g

grams

g

l

liters

l

ml

mililiters

ml

poise

units of viscosity

poise

°C

degrees Celsius

°C

°K

degrees Kelvin temperature

°K

T

temperature

°C or °K

m

meters

m

cm

centimeters

cm

s

Sedimentation Coefficient

sec

s*

s star, apparent sedimentation coefficient

sec

s20W

s20w, sedimentation coefficient corrected to 20 degrees C in pure water (but not corrected for solute concentration)

sec

s°

szero; sedimentation coefficient corrected to zero solute concentration

sec

s°20w

szero20w; sedimentation coefficient corrected to 20 degrees C in pure water and also corrected for solute concentration

sec

smax

The maximum sedimentation coefficient assuming that the sample is an anhydrous sphere

sec

f

Frictional coefficient (may inherit subscripts etc. from s)

g (sec)^(1)

k

An empirical constant that takes into account the effect of sample concentration on s

l/g

σ

sigma, reduced apparent molecular weight

cm^(2)

JD

flux due to diffusion

g (cm^(2)) (sec^(1))

D

diffusion coefficient

cm^(2) sec^(1)

D0

Maximum diffusion coefficient assuming the protein is an anhydrous sphere

cm^(2) sec^(1)

Js

Flux due to sedimentation

g cm^(2) sec^(1)

R

Gas constant 8.3144*10^7 in cgs

g mole^(1) °K ^(1)

N0

Avogadros number 6.023*10^23

mole^(1)

N

Number of residues

unitless

c

weight or mass concentration

g/l

c(r)

function of concentration at radial position r

g/l

C

Molar concentration

mole/liter

ω

Radial velocity (usually of centrifuge rotor)

sec^(1)

Mr

Molecular weight

g mole^(1)

Mp

Molecular weight of a protein in a complex

g mole^(1)

Md

Molecular weight of a denaturant in a complex

g mole^(1)

ρ

density (usually of buffer)

g/ml

vbar

partial specific volume

ml/g

η

viscosity

poise

R0

Radius of anhydrous sphere computed from molecular weight and vbar

cm

Rp

Radius of anhydrous sphere computed from molecular weight and Perrins empirical formula

cm

Rs

Stokes radius

cm

a/b

ratio of axial lengths in a model of an asymmetrical oblate or prolate

unitless

δ1

degree of hydration

unitless
