Appeal No. 1997-2364
Application 08/137,086
di or trivalent metal ion; and diafiltering the digested solution, maintaining the metal ion
concentration at a level effective to keep the selected phosphopeptides in aggregate form,
and using a molecular weight exclusion limit effective to retain at least the selected
phosphopeptides and allow the bulk of the remaining phosphopeptides to pass into a
filtrate. Although the “selected phosphopeptides” are not defined in the claim, it is clear
that they represent a subset of the total phosphopeptides in the digested solution, and that
the molecular weight exclusion limit and the metal ion concentration during diafiltration are
coordinated to permit separation of the hydrolysate into two fractions: one containing the
selected phosphopeptides, and another containing both the remaining phosphopeptides
and non-phosphorylated peptides.
Returning to Brule’s method, we find that a soluble monovalent cation salt of
phosphocaseinate
is subjected to enzymatic hydrolysis by means of at least one proteolytic
enzyme . . . the thus obtained hydrolyzate is subjected to at least one
ultrafiltration step on membranes which allow all the peptides in the
hydrolyzate to pass in the permeate; the permeate is added with at least one
bivalent cation salt capable of forming aggregates with the phosphorylated
fraction of said peptides, this leading to a solution which essentially contains
aggregates of phosphopeptides and non phosphorylated peptides; and
separation is effected by at least one ultrafiltration step between the non
phosphorylated peptides and the phosphopeptides, the latter having a larger
particle size, by bringing the solution into contact with at least one membrane
capable of retaining said phosphopeptides (column 4, lines 7-25).
Brule teaches that “the amount of [bivalent cation salt] . . . is not critical,” and “it rests
with those skilled in the art to select the bivalent compounds and amount thereof to be
6
Page: Previous 1 2 3 4 5 6 7 8 9 10 Next
Last modified: November 3, 2007