1: Anal Biochem  1988 Nov 15;175(1):114-9 

A parameterized overspeeding method for the rapid attainment of low-speed
sedimentation equilibrium.

Chatelier RC.

Section on Pharmacology, National Institute of Diabetes and Digestive and Kidney
Diseases, Bethesda, Maryland 20892.

The approach of a solution of dilute, monodisperse, globular macromolecules to
low-speed sedimentation equilibrium in an ultracentrifuge is simulated by
numerical integration of the Lamm equation. Various combinations of overspeed
time and angular velocity are used to assess the conditions needed to minimize
the time it takes the solution to attain sedimentation equilibrium. The optimal
overspeeding time and angular velocity are determined over a wide range of
values of the molecular weight (relative molar mass) of the solute and the
radial distance between the meniscus and base of the solution. The results may
be expressed as simple functions which allow facile calculation of (a) the
optimal overspeeding time and velocity, and (b) the time required to reach
sedimentation equilibrium. The results are in reasonable agreement with previous
analytical solutions which were based on several simplifying assumptions. The
parameterized overspeeding procedure is shown to be robust over a wide range of
conditions, and typically leads to a greater than 5-fold reduction in
centrifugation time.

PMID: 3245561 [PubMed - indexed for MEDLINE]