Extinction coefficients

Arp2/3 OD290 7.14uM
Actin        38.5uM

Actophorin 1mg/mL= 0.89 OD 286

Profilin 1mg/mL= 1.2 OD

An Extinction Coefficient is roughly calculated at 280 OD by:

Tyrosine 1300/amino acid x number in protein plus 5700 per amino acid

this gives you OD/molar and you can convert it to OD/uM