From: Walter Stafford <STAFFORD@bbri.org>
  To  : rasmb@bbri.org
  Date: Thu, 24 Jun 1999 20:45:32 -0400 (EDT)

charge effects

Hi RASMBers

	For those who are performing sedimentation experiments in water or
very low ionic strength buffer, you might want to consult Howard Schachman's
book "Ultracentrifugation in Biochemistry" Academic Press 1959 pp225- for a
discusion of the effect of charge on the apparent molecular weight. See
especially equation 133 which gives the limiting value in the absence of
supporting electrolyte. See also T.Svedberg and K.O Pederson "The
Ultracentrifuge" Oxford Uinversity Press, 1940. pp53 and 54 in which they give
relations for multivalent (eqn 99) and univalent (next unnumbered eqn)
counterions. The limiting relation for high ionic strength is given in eqn
101. 



Walter Stafford