as they do so, presumably from the sugars coming from triacylglycerol utiliza-
tion; and, in addition to that of cellulose, synthesis of starch also occurs. So even
though the axial sink is absent, two other sinks—cellulose and starch synthesis—
serve to drain off the products of triacylglycerol mobilization and, by preventing
their accumulation, permit the activity of the lipolytic enzymes to continue. The
activity of extracted proteolytic enzymes from the cotyledons is similarly unaf-
fected by removal of the axis, but within the cotyledons protein hydrolysis itself
is minimal. Accumulated amino acids, especially leucine and phenylalanine, as
well as the dipeptide tryptophylphenylalanine, inhibit the activity of aminopep-
tidase in the cotyledons thus preventing protein degradation.